Post by: Vin on August 24, 2010, 02:26:14 pm
Still don't get it, ask it here.
Post by: elemis on August 31, 2010, 08:15:38 am
Moving it back.
Post by: WARRIOR on September 15, 2010, 01:54:06 pm
A golfer hits the ball B a distance of 170m towards a hole H which measures 195m from the tree T to the green.If this shot is directed 10* away from the ttrue line to the hole , find the distance between his ball and the hole.
help, i cant even draw the diagram for this.
ANSWEr is : 40.4 m
Thank You u in advanced
Post by: Vin on September 15, 2010, 02:00:41 pm
QUESTION
A golfer hits the ball B a distance of 170m towards a hole H which measures 195m from the tree T to the green.If this shot is directed 10* away from the ttrue line to the hole , find the distance between his ball and the hole.
help, i cant even draw the diagram for this.
ANSWEr is : 40.4 m
Thank You u in advanced
Got it. Gimme two mins. ;)
Post by: Vin on September 15, 2010, 02:11:06 pm
Diag 1 is the basic sketch for the situation. We have to find BT.
In this case you are to use the cos rule.
a2 = b2 + c2 - 2bc . cos A
[Attachment 2]
I have renamed to points so that it fits the equation.
a2 = b2 + c2 - 2bc . cos A
a2 = 1952 + 1702 - 2 * 170 * 195 * cos 10
a2 = 66925 - 66300 . cos10
a =
a = 40.4 m
Hope you get it. I have a bad way of explaining. :P ;)
Post by: Deadly_king on September 15, 2010, 02:18:32 pm
Its a simple triangle with one side 195m and another side 170m with the angle between these two sides being 10*. The question just ask you to find the other side.
Hence you need to use cosine rule. Thats all.
Actually the question is quite misleading but not difficult :)
Post by: WARRIOR on September 15, 2010, 02:45:41 pm
i couldnt draw the diagram so it was a pain
cheers
Post by: Deadly_king on September 15, 2010, 02:53:50 pm
OOH i get it thanks vin ! i owe you a + rep but i have to spread teh love first !Dont worry dude........did it for you :)
i couldnt draw the diagram so it was a pain
cheers
Post by: WARRIOR on September 15, 2010, 08:44:53 pm
I got the length right but i cant seem to get the bearing :-\
Also this next question , is attached
Find AE easy
Angle EAC - easy
The angle of elevation from A ? hard , for me anyway
Post by: elemis on September 16, 2010, 11:55:00 am
Post by: elemis on September 16, 2010, 12:11:02 pm
I am assuming you are asking for the homeward journey bearing.
I got 18 degrees first because adjacent angles add up to 180 (162 + 18 = 180).
Next, 360-(260+18) = 82 degrees. The angle adjacent to 100 (100 = 82+18) is 80 degrees (in maroon).
Using
hence x =31.5797.... Hence, 80 - angle x = 48.4 degrees
Post by: elemis on September 16, 2010, 12:25:58 pm
See pic.
I hope my answers are right :D
Post by: WARRIOR on September 17, 2010, 06:50:16 am
but question 2
Look at your diagram edited by me
you see the 180 * angle i drew?
yea you find the angle in the small right triangle = 180-90 + 40 = 50*
Then you find the angle in the middle which is = approx 73.2
Then 180 - 73.2 + 50 = 56.8
THEN 56.8 - 90 = 33.2 <---right answer !
my teacher said you shouldnt have assumed the whne you drew that line in the middle that you cut the angle exactly into a half , you get the point?
edit : oops i forgot to attaach
Post by: elemis on September 17, 2010, 06:57:47 am
Post by: WARRIOR on September 17, 2010, 06:59:07 am
Is this a question from your textbook ?yea why?
Post by: elemis on September 17, 2010, 07:01:32 am
yea why?
What is the answer at the back say and which textbook are you using ?
Post by: WARRIOR on September 17, 2010, 07:05:44 am
What is the answer at the back say and which textbook are you using ?its says 32.6 but i made some errors while calculating so , thats why i said 33.2 anyway
beliefe it or not my front cover is cut off so i cant see the name at all but i think its DAVID RAYNER IGCSE FOR MATHEMATICS
Post by: elemis on September 17, 2010, 07:07:13 am
Post by: WARRIOR on September 17, 2010, 07:12:05 am
youll be very kind if you do question 11 for me
Post by: elemis on September 17, 2010, 07:18:45 am
Post by: elemis on September 17, 2010, 07:21:40 am
its says 32.6 but i made some errors while calculating so , thats why i said 33.2 anyway
beliefe it or not my front cover is cut off so i cant see the name at all but i think its DAVID RAYNER IGCSE FOR MATHEMATICS
I know why I got it wrong. You see in your diagram you wrote 7 m in between those two lines. I thought 7m was the length of the staright one.
See diagram.
Post by: WARRIOR on September 17, 2010, 07:25:18 am
I know why I got it wrong. You see in your diagram you wrote 7 m in between those two lines. I thought 7m was the length of the staright one.oh lol :P my bad :P wasted your time :P
See diagram.
anyway can you do question 11 if ur free?
Post by: elemis on September 17, 2010, 07:26:01 am
oh lol :P my bad :P wasted your time :P
anyway can you do question 11 if ur free?
See post no.19 for part a.
I'm doing b now.
Post by: elemis on September 17, 2010, 07:31:41 am
See pic.
Post by: WARRIOR on September 17, 2010, 07:34:08 am
Part (b) Question 11
See pic.
oh Thanks !.That was easy , its just that i cant put the words into a diagram :/ Thanks alot!
Post by: elemis on September 17, 2010, 07:37:55 am
oh Thanks !.That was easy , its just that i cant put the words into a diagram :/ Thanks alot!
Practice makes perfect ;)
No worries :)
Post by: WARRIOR on September 17, 2010, 04:07:08 pm
PAGE 196 , QUESTION 8 , (C)
thanks in advanced
Post by: elemis on September 17, 2010, 04:13:10 pm
Hence, tan 25 = h / length OA
Re-arranging we get h / tan25 = length OA
(b) Same idea as above : tan 33 = h / length OB
Re-arranging give Length OB = h/ tan33
Give me some time for (c)
Post by: WARRIOR on September 17, 2010, 04:17:29 pm
(a) Since tan x = Opposite/Adjacent
Hence, tan 25 = h / length OA
Re-arranging we get h / tan25 = length OA
(b) Same idea as above : tan 33 = h / length OB
Re-arranging give Length OB = h/ tan33
Give me some time for (c)
tyt
Post by: elemis on September 17, 2010, 04:23:34 pm
Solving this gives h = 22.7 m
Post by: WARRIOR on September 17, 2010, 04:42:33 pm
thanks
can anyone solve this question
The angle of elevation of the top of a tower is 38 from a point A due south of it. The angle of elevation of the top of the tower from another point B , due East of the tower is 29.Find teh height of the tower if the distance AB is 50m
My drawing is attached and i got the asnwer as 24.5 , while the right answer is 22.6
Post by: elemis on September 17, 2010, 04:48:08 pm
Post by: WARRIOR on September 17, 2010, 04:48:36 pm
One minute.:O
it was always 2 minutes !
Post by: elemis on September 17, 2010, 05:00:12 pm
:O
it was always 2 minutes !
Sorry dude, but I have to go out with my parents now.
Really sorry to leave you hanging, but I have to go now.
Post by: WARRIOR on September 17, 2010, 05:03:05 pm
Sorry dude, but I have to go out with my parents now.kk no prob. Later then , have a good time.
Really sorry to leave you hanging, but I have to go now.
Post by: WARRIOR on September 18, 2010, 06:30:31 am
When do we use 1/2.A.B.SIN C , and not 1/2 b x h
Post by: elemis on September 18, 2010, 06:55:07 am
I also have another question .
When do we use 1/2.A.B.SIN C , and not 1/2 b x h
You generally use 0.5*b*h when its a right angle triangle.
The other one is used when you have the angle between two sides of a known length and the triangle ISNT right angled.
Post by: S.M.A.T on September 18, 2010, 08:10:44 am
allright thanks ! i did the same thing but i thought there was another way to add the TANs rather than all of this mess
thanks
can anyone solve this question
The angle of elevation of the top of a tower is 38 from a point A due south of it. The angle of elevation of the top of the tower from another point B , due East of the tower is 29.Find teh height of the tower if the distance AB is 50m
My drawing is attached and i got the asnwer as 24.5 , while the right answer is 22.6
Your drawing confused me.'B' should be on the east of 'T' i.e TB should be perpendicular to TA
Here :)
Post by: S.M.A.T on September 18, 2010, 08:24:43 am
You generally use 0.5*b*h when its a right angle triangle.+
you can also use it in any triangle if you know the length of a side and the perpendicular of that side
Example below:
Post by: astarmathsandphysics on September 18, 2010, 08:43:40 am
Post by: astarmathsandphysics on September 18, 2010, 08:47:28 am
Post by: WARRIOR on September 18, 2010, 08:49:51 am
MUCH !!!!! i could have never solved it without you ! i had to draw a 3d diagram to understand it ! thank you asiftasfiq93 very much for you time and effort !!!!!!!!!!!!!!!!!! By the way your hand writing is very readable , i didnt even have to zoom !
thanks a million man . + rep !!!!!!!!!!!!!!!!!
ps : thank you also sir ( astarmathsandphysics ) for your time and effort ! + rep to you too ! !
Post by: S.M.A.T on September 18, 2010, 10:17:55 am
Post by: WARRIOR on October 02, 2010, 02:28:10 pm
Amodel of the truck is made using a scale of 1:50
Calculate the capacity of the model in millilitres
200?
Post by: Deadly_king on October 02, 2010, 03:32:30 pm
A truck has a capacity of 10,000 litresThis implies that 50 litres will be represented by 1
Amodel of the truck is made using a scale of 1:50
Calculate the capacity of the model in millilitres
200?
Therefore 10,000 litres will be represented by 1/500 * 10,000 = 200
But 200.......it's in terms of litres.
So you need to convert in terms of millilitres ---> 200 * 103( Ilitre = 103 ml)
Hence answer is 200,000ml.
Post by: HUSH1994 on October 06, 2010, 02:49:52 pm
Post by: Vin on October 06, 2010, 03:32:29 pm
what are ALL the matrix transformations i need for IGCSE?including all reflections,rotation,translation,shear,stretch,enlargement?Please??
https://studentforums.biz/math-147/transformation-martices-igcse/msg167877/#msg167877
Post by: WARRIOR on October 15, 2010, 06:38:07 am
2.A bank pays interest of 11% on 6000 in a deposit account..After how many years will the money have trebled
3.A tree grows in height by 21% per year. It is 2m tall after one year. After how many more years will the tree be over 20m tall?
thx in advanced.
Post by: elemis on October 15, 2010, 07:05:55 am
100 * 1.10n = 200
Solving for n give : 1.10n = 2
Hence, log 2 / log 1.1 = 7.27 years (3 s.f.)
Therefore answer is 8 years. Since after 7.27 years there will only be 199.9 people.
Post by: WARRIOR on October 15, 2010, 07:48:43 am
Let the initial population be 100 and the number of years after which the population doubles let it be n.
100 * 1.10n = 200
Solving for n give : 1.10n = 2
Hence, log 2 / log 1.1 = 7.27 years (3 s.f.)
Therefore answer is 8 years. Since after 7.27 years there will only be 199.9 people.
3. The answer at the end n = 12.1 , and so 1.21^12.1 x 2= 20m exactly
why is the asnwer in the book 13?
ok but for the next one , the answer in my book says 12 years why?
6000 x 1.11^n = 18000
1.11^n= 3
thergfore log 3/ log 1.11
=10.5
and anywy the anwer in the book says 12 and 6000 x 1.11^12 = 20000 +
Post by: astarmathsandphysics on October 15, 2010, 12:30:41 pm
Post by: Galleria on October 15, 2010, 04:35:36 pm
Q 21 b .
I don't get it . how is it 960 ?
Post by: elemis on October 15, 2010, 04:43:56 pm
Post by: elemis on October 15, 2010, 04:52:24 pm
The car travels faster than the truck from 15 s to 55 s
Hence, I 've split the relevant area into two trapeziums. One red and one blue.
Using the area of a trapezium formula for the red one :
0.5* (12+36)*30 = 720
Using the same formula for the blue one :
0.5 * (36+12)*10 = 240
Hence, 240 + 720 = 960 m
The area of a trapezium is given by this formula :
0.5 (sum of the length of parallel side) * perpendicular distance between the two parallel sides
Post by: Deadly_king on October 15, 2010, 06:04:59 pm
ok but for the next one , the answer in my book says 12 years why?
6000 x 1.11^n = 18000
1.11^n= 3
thergfore log 3/ log 1.11
=10.5
and anywy the anwer in the book says 12 and 6000 x 1.11^12 = 20000 +
You made a little mistake there dude. It actually is similar to a general progression ;)
The required solution :
6000 x 1.11(n-1) = 3(6000)
Simplify it and you'll be getting n = 11.5 which can be taken as 12. But the best answer is 11.5
Same principle is applied for question 3 and 1.
3) 2 x 1.21(n-1) = 20
You just need to simplify and you'll get n = 13
1) 100 X 1.1(n-1) = 2(100) -----> n = 8.27 which can be taken as 8 ;)
Hope it helps :)
Post by: Galleria on October 16, 2010, 05:18:36 am
now i get it
i kept getting the answer 480 . now i get that we gotta go below too . THANKS !
Post by: elemis on October 16, 2010, 05:32:29 am
ohhhhhhhhhh lol
now i get it
i kept getting the answer 480 . now i get that we gotta go below too . THANKS !
No worries ;)
Post by: WARRIOR on October 20, 2010, 04:05:38 pm
You made a little mistake there dude. It actually is similar to a general progression ;)
The required solution :
6000 x 1.11(n-1) = 3(6000)
Simplify it and you'll be getting n = 11.5 which can be taken as 12. But the best answer is 11.5
Same principle is applied for question 3 and 1.
3) 2 x 1.21(n-1) = 20
You just need to simplify and you'll get n = 13
1) 100 X 1.1(n-1) = 2(100) -----> n = 8.27 which can be taken as 8 ;)
Hope it helps :)
i never heard the thing about the n-1 but it seems to get the right answers ! thx much !!
i have another question
A wallet contains $40 and has 3 times as many $1 notes as $5 notes . Find the no. of each kind.
Post by: Deadly_king on October 20, 2010, 04:18:33 pm
i never heard the thing about the n-1 but it seems to get the right answers ! thx much !!
i have another question
A wallet contains $40 and has 3 times as many $1 notes as $5 notes . Find the no. of each kind.
Anytime :)
Given the ratio of $3:$5 = 3:1(5) ---->$40 represents (3 + 1(5))=8 shares
Hence 1 share represents 40/8 = $5
Number of $1 = 3(5) = 15
Number of $5 = 5
Hope it helps :)
Post by: WARRIOR on October 20, 2010, 04:31:51 pm
Anytime :)
Given the ratio of $3:$5 = 3:1 ---->$40 represents (3 + 1)=4 shares
Hence 1 share represents 40/4 = $10
Number of $1 = 10
Number of $5 = 3(10) = 30
Hope it helps :)
tyvm + rep
Post by: Vin on October 20, 2010, 04:34:50 pm
Number of $1 = 10
Number of $5 = 3(10) = 30
Wouldn't that make it $160 in total? :/
I think no. of $1 = 15 and no. of $5 = 5
Post by: Deadly_king on October 20, 2010, 05:17:05 pm
Wouldn't that make it $160 in total? :/
I think no. of $1 = 15 and no. of $5 = 5
Yeah.......your answers are right!
I forgot the $5.............wait i'll modify my post :-[
Post by: ~aanchal~ on October 31, 2010, 10:20:43 am
Post by: elemis on October 31, 2010, 12:01:51 pm
m/j 2009 locus question pls soooooonnn.. exams tomm
Paper 2 or 4 ?
Post by: elemis on October 31, 2010, 12:08:09 pm
Post by: ~aanchal~ on October 31, 2010, 12:26:17 pm
Thank You ALOTTT
Post by: elemis on October 31, 2010, 12:31:43 pm
may june 2010 circle question second variant (q 11)
Thank You ALOTTT
hang on.
Post by: elemis on October 31, 2010, 12:40:31 pm
Post by: ~aanchal~ on October 31, 2010, 12:40:55 pm
hang on.not done??
Post by: elemis on October 31, 2010, 12:46:07 pm
not done??
Check the post above yours.
Post by: ~aanchal~ on October 31, 2010, 12:57:03 pm
Check the post above yours.thanks alot cleared my doubt...
i'll check if i've any other doubt
wat are ur tips for my p2 exam tomm
Post by: ~aanchal~ on October 31, 2010, 01:04:16 pm
Post by: The Golden Girl =D on October 31, 2010, 01:06:40 pm
Don't Panic
Do NOT correct your exam paper with your friends after your Done ;)
Good luck :D
Post by: ~aanchal~ on October 31, 2010, 01:09:53 pm
Concentratepls answer the question above
Don't Panic
Do NOT correct your exam paper with your friends after your Done ;)
Good luck :D
Post by: elemis on October 31, 2010, 01:11:49 pm
o/n 2009 second variant q 18
2 minutes.
Post by: elemis on October 31, 2010, 01:16:22 pm
Thus, m = 2
Next we find the point at which y = 2x +8 crosses the X AXIS. This is the same as point A as marked on the diagram.
Hence, at this point the y coordinate is zero. Thus we get :
2x +8 = 0
x = -4
Since the distance between A and B is 9 we add 9 to -4 to get the corresponding X INTERCEPT for the other line. In this case the x intercept is (5,0)
We input the coordinate (5,0) into y = 2x +c
We get 0 = 2*5 + c
c = -10
Post by: ~aanchal~ on October 31, 2010, 01:42:44 pm
Parallel lines ALWAYS have the same gradient.thanx alott
another question
m/j 2009 q 17(B)
Post by: elemis on October 31, 2010, 01:45:05 pm
Post by: elemis on October 31, 2010, 01:49:23 pm
So Place your tracing paper over the page and trace the grid and triangle.
With your tracing paper still on top of the page place your pencil on the point 4,4.
Rotate your TRACING paper 90 degrees to the right i.e. if the original position of your tracing paper was portrait it should now be landscape.
Make a note of the vertices of the triangle as in its new position.
Draw in the triangle.
Post by: ~aanchal~ on October 31, 2010, 04:14:53 pm
FAST
Post by: ~aanchal~ on October 31, 2010, 04:23:16 pm
You are allowed to use tracing paper.pls answer
So Place your tracing paper over the page and trace the grid and triangle.
With your tracing paper still on top of the page place your pencil on the point 4,4.
Rotate your TRACING paper 90 degrees to the right i.e. if the original position of your tracing paper was portrait it should now be landscape.
Make a note of the vertices of the triangle as in its new position.
Draw in the triangle.
Post by: Vin on October 31, 2010, 06:16:51 pm
m/j 2003 p2 q 17
FAST
Q.17 a) [Attachment]
b) [Attachment]
c)
Matrix of Object * A = Matrix of Image.
|O| * |A| = |I|
(0 2) * (a b) = (0 6)
(2 2) (c d) (2 6)
You can eliminate the coordinates of the bas as it is common for both - the image as well as the object.
Now, you multiply both the matrix as you normally do. You get:
(0 + 2c 0 + 2d)
(2a+2c 2b+2d)
Therefore,
2c = 0
2a + 2c = 2
2d = 6
2b + 2d = 6
^^Look at the colour combinations. The values corresponding are equal.
Solve the eqns.
2c = 0
c = 0
2a + 2 * 0 = 2
a = 1
2d = 6
d = 3
2b + 2*3 = 6
2b = 0
b = 0
Arrange the values of a b c and d to |A|
So, |A| =
(1 0)
(0 3)
Post by: Arthur Bon Zavi on November 04, 2010, 05:05:55 am
Post by: Galleria on November 05, 2010, 09:41:03 am
like if you get an A in paper 2 and 4 both is that A* ?
Post by: Arthur Bon Zavi on November 05, 2010, 03:07:59 pm
loool how do we get an A* in math ?
like if you get an A in paper 2 and 4 both is that A* ?
Well, what you said is one criteria !
Another criteria is that that also have many other criteria s with which they grade candidates.
You will come to know when you have earned your results. ;)
Post by: **RoRo** on December 11, 2010, 12:00:50 pm
The capacity of a jug is 3.5 litres correct to the nearest 0.1 litre.
The capacity of a glass is 0.25 litres correct to the nearest 0.01 litre.
b) Calculate the greatest number of glasses which you can be sure to fill from a full jug.
Can someone please explain to me how do you arrive to this answer? Thanks!
Post by: elemis on December 11, 2010, 12:08:31 pm
Post by: elemis on December 11, 2010, 12:11:06 pm
Paper 2, June 2001.
The capacity of a jug is 3.5 litres correct to the nearest 0.1 litre.
The capacity of a glass is 0.25 litres correct to the nearest 0.01 litre.
b) Calculate the greatest number of glasses which you can be sure to fill from a full jug.
Can someone please explain to me how do you arrive to this answer? Thanks!
We need to find the largest possible capacity of the jug and the SMALLEST possible capacity of the glass.
LARGEST capacity of jug = 3.55
SMALLEST capacity of glass = 0.255
Hence, 3.55/0.255 = 13 glasses (dont round up)
Post by: SauD~ on January 20, 2011, 08:17:35 am
Indices:- 9^1/2 x 3^5/2
--------------
3^2/3 x 3^-1/6
Graphs of function:- a) Plot a graph of function equation y=2x^2-5x-5 for -2 =<x=<5.
b) Use the graph to solve the 2x^2-5x-5=0.
c) Show you method clearly, use the graph to solve the equation 2x^2-3x=10.
part c) with the method is necessary :)
if you need the answer then the answer for indices is 27 and the answer for graph thing of part c) is x= -1.6 and 3.1
x --> multiplication sign & x --> X, the unknown value..
Thanks, :)
Post by: Amii on January 20, 2011, 09:10:32 am
Quote
Indices:- 9^1/2 x 3^5/2
--------------
3^2/3 x 3^-1/6
9^1/2 x 3^5/2
9^1/2 = Square root of 9 = 3 which is same as 3^1
so 3^1 X 3^5/2
1/1 + 5/2 = 3.5
1x2 + 5x1 = 2 + 5 = 7 = 3.5
---- ---- ----- --
1x2 2x1 2 2
3^3.5 or 3^7/2
3^2/3 x 3^-1/6
2/3 -1/6 = 3/6
2x2 - 1x1 = 4-1 = 3
---- ---- ---- --
3x2 6x1 6 6
so 3^3/6
(3^7/2 ) / (3^3/6)
(7/2) - (3/6) = 3
7x3 - 3x1 = 21-3 = 18 = 3
--- --- ----- ---
2x3 6x1 6 6
so 3^3 = 27
Okay saud? :D
Post by: Most UniQue™ on January 20, 2011, 09:36:46 am
A,B,C,D are the four corners of a rectangular plot marked out on level ground.Given that the bearing of B from A is 090*, calculate the bearing of:
a) B from C
b) A from C
c) D from C
Plz explain it so that I cn get it Thanks
Post by: astarmathsandphysics on January 20, 2011, 10:34:36 am
Post by: Most UniQue™ on January 20, 2011, 10:35:12 am
I will put up a diagram now.ok Thanks ill be waiting
Post by: astarmathsandphysics on January 20, 2011, 10:42:49 am
Post by: SauD~ on January 20, 2011, 10:49:49 am
ANNIE THANKS A LOT :D but i have got a easier method by using my brain
9^1/2 x 3^5/2
9^1/2 = Square root of 9 = 3 which is same as 3^1
so 3^1 X 3^5/2
1/1 + 5/2 = 3.5
1x2 + 5x1 = 2 + 5 = 7 = 3.5
---- ---- ----- --
1x2 2x1 2 2
3^3.5 or 3^7/2
3^2/3 x 3^-1/6
2/3 -1/6 = 3/6
2x2 - 1x1 = 4-1 = 3
---- ---- ---- --
3x2 6x1 6 6
so 3^3/6
(3^7/2 ) / (3^3/6)
(7/2) - (3/6) = 3
7x3 - 3x1 = 21-3 = 18 = 3
--- --- ----- ---
2x3 6x1 6 6
so 3^3 = 27
Okay saud? :D
:P :P
9^1/2 = ,/9 = 3 ,/ --- > square root sign :-[
then all are 3
so we can add same number when multiply and subtract when divide so:
3^(1 + 5/2) - (2/3 + (-1/6)) so the answer comes 3^3 = 27 ;) :D
BUT I REALLY APPRECIATE YOUR HELP, ANNIE
Post by: SauD~ on January 20, 2011, 10:57:04 am
hereSir, wasn't B suppose to be a bearing from A at 90 degrees?
Post by: Most UniQue™ on January 20, 2011, 10:58:37 am
herebut Sir the answer u gave is wrong!
a) 310
b)270
c)220
Post by: SauD~ on January 20, 2011, 11:06:36 am
but Sir the answer u gave is wrong!Answer key?
a) 310
b)270
c)220
Post by: Amii on January 20, 2011, 11:51:36 am
ANNIE THANKS A LOT :D but i have got a easier method by using my brainLOL that's cool ;D
:P :P
9^1/2 = ,/9 = 3 ,/ --- > square root sign :-[
then all are 3
so we can add same number when multiply and subtract when divide so:
3^(1 + 5/2) - (2/3 + (-1/6)) so the answer comes 3^3 = 27 ;) :D
BUT I REALLY APPRECIATE YOUR HELP, ANNIE
And not a problem at all :D
Post by: Arthur Bon Zavi on January 20, 2011, 12:10:17 pm
Post by: astarmathsandphysics on January 20, 2011, 01:32:36 pm
Sir, wasn't B suppose to be a bearing from A at 90 degrees?
B says A from C
When It says 'from C' it means you are at C and want to go to A
Post by: SauD~ on January 20, 2011, 02:17:48 pm
Bearings:Sir, i meant the bold part in above quote.
A,B,C,D are the four corners of a rectangular plot marked out on level ground.Given that the bearing of B from A is 090*, calculate the bearing of:
a) B from C
b) A from C
c) D from C
Plz explain it so that I cn get it Thanks
Post by: astarmathsandphysics on January 20, 2011, 02:21:37 pm
Post by: astarmathsandphysics on January 20, 2011, 02:27:53 pm
Post by: SauD~ on January 20, 2011, 02:46:48 pm
Post by: astarmathsandphysics on January 20, 2011, 10:44:10 pm
Post by: SauD~ on January 21, 2011, 10:58:46 am
Post by: The Golden Girl =D on January 21, 2011, 11:27:25 am
Can anyone tell me how to solve questions like 20(b)(i) :-[
It's Alright with LOADS of practice you'll get the hang of it. :D
(x-3)2
is the SAME as (x-3)(x-3)
the easiest way is to follow this Rule :
(a-b)2
a2 - 2ab + b2
(x-3)2
x2 - 2(x*-3) + (3)2
x2 + 6x + 9
or the long method which is ;
(x-3) (x-3)
x2 -3x -3x +9
x2 -6x + 9 :)
Post by: elemis on January 21, 2011, 11:38:35 am
Can anyone tell me how to solve questions like 20(b)(i) :-[
How long ago did you start your IGCSE course ?
When are your real IGCSEs ?
Post by: SauD~ on January 21, 2011, 11:40:52 am
It's Alright with LOADS of practice you'll get the hang of it. :Dno no Nuna i knew that ;D
(x-3)2
is the SAME as (x-3)(x-3)
the easiest way is to follow this Rule :
(a-b)2
a2 - 2ab + b2
(x-3)2
x2 - 2(x*-3) + (3)2
x2 + 6x + 9
or the long method which is ;
(x-3) (x-3)
x2 -3x -3x +9
x2 -6x + 9 :)
the question below that one... never have done that in class ;D
Tomorrow is the exam... and i did the past paper i got 66/70 :D
only because of that and some silly mistakes :D
Post by: Amii on January 21, 2011, 12:00:07 pm
x2-6x + 10
=(x-3)2 -32 +10
=(x-3)2 +1
hence p=3 and q =1
Post by: SauD~ on January 21, 2011, 12:09:37 pm
By the method of completing the squarewhere did 6x turned it only 3 ???
x2-6x + 10
=(x-3)2 -32 +10
=(x-3)2 +1
hence p=3 and q =1
help! can you explain :(
Post by: Amii on January 21, 2011, 12:21:03 pm
where did 6x turned it only 3 ???That's the way you half it :D
help! can you explain :(
x2-ax+b
=(x-1/2a)2 - (1/2a)2 + b
x2+ax+b
=(x+1/2a)2 - (1/2a)2 + b
You want me to give you some example questions to solve?
Post by: Arthur Bon Zavi on January 21, 2011, 12:24:28 pm
where did 6x turned it only 3 ???
help! can you explain :(
There's one formula to solve these type of sums, but will be covered in AS Levels (Pure Mathematics 1)
Equation will be in the form x2 + bx + c = 0
(x + 1/2b)2 = x2 + bx + 1/4b2, so x2 + bx = (x + 1/2 b)2 - 1/4b2
Adding c to both the sides will give :
x2 + bx+ c = (x2 + bx) + c = { (x + 1/2b)2 - 1/4b2 } + c
I do this way :
x2-6x + 10
(x2 - 6x + 9 + 1)
(x - 3)2 + 1
Therefore, p=3 and q = 1
Post by: SauD~ on January 21, 2011, 12:30:45 pm
but where did the x go, we can't just remove the x as we don't know the value :-[
Post by: Arthur Bon Zavi on January 21, 2011, 12:37:51 pm
i know i got some simple and stupid,
but where did the x go, we can't just remove the x as we don't know the value :-[
You know what ! You can REMOVE whatever you want.
BUT
then you will not know when examiner will REMOVE the marks. :P
Post by: SauD~ on January 21, 2011, 12:40:43 pm
You know what ! You can REMOVE whatever you want.i will call my mommy, because this big guy is bullying :'( :'(
BUT
then you will not know when examiner will REMOVE the marks. :P
Post by: Amii on January 21, 2011, 12:43:19 pm
=(x-3)2 -32 +10
Look it will be the same thing when you solve it
=(x-3)2 -32 +10
=(x2 - (2*3*x)+32) -32 +10
=x2- 6x + 9 -9 + 10
=x2- 6x +0 + 10
=x2 -6x +10
Again you are getting back the same thing right?
Now disappearing of x is okay? :P
Post by: SauD~ on January 21, 2011, 12:54:26 pm
(x-3)(x-3) - 9 + 10
x2 -3x-3x +9 + 1
then:
x2 -6x + 10
:o :o :o :o
i got it :D :D :D :D
1st factorize the question
thats was kiddish question :P
THANKS ANNIE ;D
Post by: Amii on January 21, 2011, 12:57:53 pm
(x-3)^2 - 3^2 +10 would be:No problem shona :D
(x-3)(x-3) - 9 + 10
x^2 -3x-3x +9 + 1
then:
x^2 -6x + 10
:o :o :o :o
i got it :D :D :D :D
1st factorize the question
thats was kiddish question :P
THANKS ANNIE ;D
I will give you some "completing the square" method examples - Later
Now I gotta go take my bath :D
Post by: SauD~ on January 21, 2011, 12:59:27 pm
No problem shona :Dannie zanks, if i want anything i would ask, now i will get A* ;D ;D
I will give you some "completing the square" method examples - Later
Now I gotta go take my bath :D
Post by: Arthur Bon Zavi on January 21, 2011, 01:01:47 pm
annie zanks, if i want anything i would ask, now i will get A* ;D ;D
One ?
Post by: SauD~ on January 21, 2011, 01:02:15 pm
One ?seven seven :D :D :D
Post by: ahmed_eg on January 21, 2011, 02:07:26 pm
number 7
HELP!
Post by: The Golden Girl =D on January 21, 2011, 02:13:06 pm
b] 72 -> 60
x -> 100
x = (72*100)/60 = 120 marks.
I hope I helped =]
Post by: SauD~ on January 21, 2011, 02:43:57 pm
a] 68/80 * 100 = 85 %in brief way for part b)
b] 72 -> 60
x -> 100
x = (72*100)/60 = 120 marks.
I hope I helped =]
72 = 60/100* x
so the 100 moves to right side
so it comes as 72*100 = 7200
7200 = 60*x
then,
7200/60 = x
120 = x
done :D
Post by: SauD~ on February 15, 2011, 10:46:03 am
What is acute angle?
Thanks,
Post by: elemis on February 15, 2011, 11:09:17 am
A piece of cake question.. :-[
What is acute angle?
Thanks,
Any angle less than 90 degrees.
Post by: SauD~ on February 15, 2011, 11:34:25 am
Any angle less than 90 degrees.hmm, ok, but what if there is a question
"measure the acute angle if the diagram"
so which angle will we take when both are acute angle.. :-\
The question number is 18th..
Post by: Vin on February 15, 2011, 12:27:37 pm
Post by: SauD~ on February 15, 2011, 01:42:37 pm
Theres just one acute angle between the two lines you draw :/i am sorry, i got it before you helped me... :)
i make so many silly mistakes :P :-[
Thanks anyways :-[
Post by: SauD~ on March 12, 2011, 05:52:17 pm
http://xtremepapers.net/CIE/Cambridge%20IGCSE/0580%20-%20Mathematics/0580_w10_qp_41.pdf
I got this paper in mocks, i did it correct but i forgot how i did :-[
It is x * (72x - 2x) ---> i forgot how i found this :-[
Thanks
Post by: $tyli$h Executive on March 12, 2011, 07:11:24 pm
I need help in question number three, part 1.
http://xtremepapers.net/CIE/Cambridge%20IGCSE/0580%20-%20Mathematics/0580_w10_qp_41.pdf
I got this paper in mocks, i did it correct but i forgot how i did :-[
It is x * (72x - 2x) ---> i forgot how i found this :-[
Thanks
The breadth of the rectangular enclosure is X.
Suppose the length is Y.
Total length of Fencing (given in question) = 72 metres. Thus total length of 3 sides = X + X+ Y=72 metres
Y = 72-2X
------------
Area = length X Breadth
=> X x Y
=> X x (72-2X)
=> 72X - 2X2
Done!
Post by: SauD~ on March 12, 2011, 07:15:25 pm
The breadth of the rectangular enclosure is X.Thanks man
Suppose the length is Y.
Total length of Fencing (given in question) = 72 metres. Thus total length of 3 sides = X + X+ Y=72 metres
Y = 72-2X
------------
Area = length X Breadth
=> X x Y
=> X x (72-2X)
=> 72X - 2X2
Done!
+rep :D
i now noticed that 72 meter is total perimeter -.-
i thought it was the length which you mentioned as Y.
Thanks :D
Post by: $tyli$h Executive on March 12, 2011, 07:19:45 pm
Thanks man
+rep :D
i now noticed that 72 meter is total perimeter -.-
i thought it was the length which you mentioned as Y.
Thanks :D
You're welcome! :)
Post by: moar on October 18, 2011, 02:28:32 pm
Find the value of x :
(2/3)^x = 81/16
Thx in advance :)
Post by: Arthur Bon Zavi on October 18, 2011, 02:36:46 pm
Can you help me with this indices question...
Find the value of x :
(2/3)^x = 81/16
Thx in advance :)
To remove the x from power, multiply both the sides by log.
(2/3)x = (81/16)
x * log (2/3) = log (81/16)
x = log (81/16) / log (2/3)
x = -4
Does this help ?
Post by: bro96 on October 24, 2011, 06:51:37 am
How do you find a matrix representing a transformation when given the start and finished result?
Post by: Ghost Of Highbury on October 24, 2011, 10:42:02 am
sqrt(3) + 1 - sqrt(4+sqrt(12))
Post by: Arthur Bon Zavi on October 24, 2011, 10:52:04 am
how do you simplify this without using a calculator
sqrt(3) + 1 - sqrt(4+sqrt(12))
Seems like you are taking IGCSE Mathematics again. :P ::)
Post by: Alpha on October 24, 2011, 11:49:32 am
how do you simplify this without using a calculator
sqrt(3) + 1 - sqrt(4+sqrt(12))
Your questions are always interesting, even after such a long time Adi! :D
How are you, by the way? Studies and all? :)
Okay, so for this one, you just gotta find a way to arrange the expressions so that they're similar. It takes me less time to jot it down, see attachment. :)
Post by: Ghost Of Highbury on October 25, 2011, 07:55:02 am
Your questions are always interesting, even after such a long time Adi! :D
How are you, by the way? Studies and all? :)
Okay, so for this one, you just gotta find a way to arrange the expressions so that they're similar. It takes me less time to jot it down, see attachment. :)
Haha, i'm good! What about you?
And thanks for the answer (Y)
Post by: Arthur Bon Zavi on October 25, 2011, 07:57:08 am
Post by: Alpha on October 25, 2011, 11:50:34 am
Haha, i'm good! What about you?
And thanks for the answer (Y)
I'm good too. Having exams. ;D
And you're welcome Adi. :)
This was a query ? I thought you were having a quiz time. :P
Haha! Me too, actually! :D
Post by: imrohan on October 29, 2011, 02:12:41 pm
Post by: NotAbod on October 29, 2011, 05:22:55 pm
some good questions are there.
Post by: Star xD on October 30, 2011, 04:54:12 pm
That is, I don't understand the I & J thing, in which we are supposed to find the matrix that shows a particular transformation.
I had no choice, so I mugged up the matrices, but am still confused if something comes that I haven't done.
I would really appreciate if someone could explain to me how to find the matrix of a particular transformation.
Also, the difference between a shear, & stretch.
Post by: NotAbod on October 30, 2011, 04:57:15 pm
for shear and stretch, check attachments
Post by: Star xD on October 30, 2011, 05:04:03 pm
Thanks for the notes.
I had a doubt in Enlargement :
in my school I was taught that the co-ordinates for an enlarged object can be found by multiplying the distance of all the points of the object & the centre with the scale factor & then moving those many spaces from the centre. But on GCSE Bitesize, its just mentioned that we can just multiply the co-ordinates of the object with the scale factor to get the co-ordinates of the image. Is this only true when the centre is (0,0) or otherwise too?
Post by: NotAbod on October 30, 2011, 05:07:48 pm
Post by: astarmathsandphysics on October 30, 2011, 05:10:05 pm
An enlargement is always a multiple of the identity matrix
Post by: imrohan on October 30, 2011, 05:11:03 pm
Post by: astarmathsandphysics on October 30, 2011, 05:12:21 pm
Post by: astarmathsandphysics on October 30, 2011, 05:13:04 pm
Post by: NotAbod on October 30, 2011, 05:14:06 pm
Post by: Star xD on October 30, 2011, 05:16:18 pm
Try this too
An enlargement is always a multiple of the identity matrix
Thanks. :)
So, is it okay to multiply the co-ordinates of the object with the scale factor for co-ordinates of the image?
Post by: astarmathsandphysics on October 30, 2011, 05:19:25 pm
Notice too that if the scale factor is k, the area is multiplied by k^2
Post by: Star xD on October 30, 2011, 05:21:37 pm
yes if the centre of enlargement is the origin. That is what I assumened when I said the matrix for an enlargement is a multiple of the identity.
Notice too that if the scale factor is k, the area is multiplied by k^2
Thanks a lot. :)
Post by: daniyal on November 17, 2011, 04:00:14 pm
calculate bearig b frm c, a frm c, d frm c!
Post by: daniyal on November 17, 2011, 04:02:28 pm
Post by: astarmathsandphysics on November 17, 2011, 07:49:01 pm
Post by: ~ Miss Relina ~ on April 21, 2012, 12:01:50 am
http://www.xtremepapers.com/papers/CIE/Cambridge%20IGCSE/Mathematics%20(0580)/0580_w05_qp_4.pdf
Q 7 ( c)(ii)
Post by: Dhampiresa on May 12, 2012, 10:35:13 am
http://www.xtremepapers.com/papers/CIE/Cambridge%20IGCSE/Mathematics%20(0580)/0580_s11_qp_42.pdf
question 8 (b) (ii)
Post by: Saladin on October 02, 2012, 06:38:21 pm
how to solve this, which co-ordinates i need to use to find the inverse :S!
http://www.xtremepapers.com/papers/CIE/Cambridge%20IGCSE/Mathematics%20(0580)/0580_s11_qp_42.pdf
question 8 (b) (ii)
Not inverse, this is simply stretch. Check your IGCSE Math book in the Matrices chapter, you should have an example like this there. I am not going to solve it for you, because then you would not learn what its all about.
Post by: astarmathsandphysics on October 03, 2012, 10:10:15 am
Divide the amount of water in cm^3 by this. I make the volume 1.512*10^9
the time is 1.512*10^9/6872=220000 seconds
or 220000/3600 =61 hours or 2 days 13 hours
Post by: MalloryKnox on October 10, 2012, 11:37:57 am
Jenny uses her mum's scone recipe to make cheese scones.
Her recipe uses a mixture of self-raising flour, butter and cheese in the ration 6:2:1 by weight
In her kitchen Jenny has:
2kg self raising flour
500g butter
200g cheese
When Jenny makes cheese scones each scone weighs about 45g.
Work out the largest number of cheese scones that Jenny can make.
Post by: Dasith on October 11, 2012, 05:20:58 am
Well in the ratio the smallest portion used is the cheese(which is also the limiting factor you can find this by bringing 2kg : 500 g : 200g into a ratio too) which contributes to the mixture by 1/9 you arrive @ the 9 by adding (6+2+1).
If this was the case : weight of final mixture multiplied by 1/9 should give you 200..
let us take weight of final mixture as X
X * 1/9 = 200
X =200 x 9
X =1800 grams
so we have the weight of the final mixture(this would the the best possible mixture jenny could come up with assuming she intends to make as many cheese scones as possible).
And the largest amount of cheese scones she can make = 1800 / 45
=40
Post by: astarmathsandphysics on October 11, 2012, 02:11:03 pm