IGCSE/GCSE/O & A Level/IB/University Student Forum
Qualification => Subject Doubts => GCE AS & A2 Level => Math => Topic started by: Twinkle Charms on May 22, 2010, 08:51:44 am
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Find the derivatives of
(a) ln(1-2x)
(b) ln(a+bx)
(c) ln(x^2(x-1))
(d) ln(2x)
please post the answers asap i did it buh want to check , a bit confused, Thank You.
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wow 10 views ns till no reply?? =(
i got math exam ppl, need help...
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wait ill ask a friend she might know she takes maths
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its probably cause of the implication of derivative. what do you mean dirivative of the ln functions. i dont think we need that for p3
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my friend says the questions dont make sense lol
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d/dx [ln f(x)] = f '(x)/ f(x), where f ' (x) is the derivative of f(x).
Derivatives:
(a) ln(1-2x) > -2/ (1-2x)
(b) ln(a+bx) > b/ (a+bx)
(c) ln(x^2(x-1)) >>> clear this one, power is only 2 or 2(x-1)?
I think you forgot to add the brackets, must have been ln((x^2)(x-1)).
For this one, use the properties of logarithms. ln ((x^2)(x-1)) = ln (x^2) + ln (x-1)
Differentiate by step to get the derivative.
ln (x^2) > 2x/ (x^2)
ln (x-1) > 1/(x-1)
Therefore, ln (x^2) + ln (x-1) = 2x/ (x^2) + 1/(x-1)
Simplify further if you want.
(d) ln(2x) > 2/2x
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d/dx [ln f(x)] = f '(x)/ f(x), where f ' (x) is the derivative of f(x).
Derivatives:
(a) ln(1-2x) > -2/ (1-2x)
(b) ln(a+bx) > b/ (a+bx)
(c) ln(x^2(x-1)) >>> clear this one, power is only 2 or 2(x-1)?
I think you forgot to add the brackets, must have been ln((x^2)(x-1)).
For this one, use the properties of logarithms. ln ((x^2)(x-1)) = ln (x^2) + ln (x-1)
Differentiate by step to get the derivative.
ln (x^2) > 2x/ (x^2)
ln (x-1) > 1/(x-1)
Therefore, ln (x^2) + ln (x-1) = 2x/ (x^2) + 1/(x-1)
Simplify further if you want.
(d) ln(2x) > 2/2x
thankyou alpha, n
its x square multiplied by x-1, so for it we open the brackets n then differientiate? N how to do the diff. part?
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its probably cause of the implication of derivative. what do you mean dirivative of the ln functions. i dont think we need that for p3
yes ofc its there in p3, the main thing dude :p
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oh woops haha , my mistake i didnt take derivative as differentiate. makes a load of sense now, i can explain here if the you dont understand the guy above
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oh woops haha , my mistake i didnt take derivative as differentiate. makes a load of sense now, i can explain here if the you dont understand the guy above
nop i got her, actually i did it just wanted to confirm, cz sum1 was confusing me :|
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oh and also i find vectors difficult, if someone can gimme good notes or site from which to refer, Vectors in 2D n 3D? the vector equation n all tht crap :|
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thankyou alpha, n
its x square multiplied by x-1, so for it we open the brackets n then differientiate? N how to do the diff. part?
ln [x^2(x-1)] = ln [x^(2x-2)]
Using laws of indices,
= ln (x^2x/ x^2)
Using laws of logarithms,
= ln (x^2x) - ln (x^2)
Derivative > 2x. x^(2x-1) {which can be simplified to 2x^(2x-1+1)= 2x^2x}/ x^(2x) - 2x/ x^2
= 2x^2x/ x^2x - 2x/ x^2
This one's more complex.
Welcome~
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ln [x^2(x-1)] = ln [x^(2x-2)]
Using laws of indices,
= ln (x^2x/ x^2)
Using laws of logarithms,
= ln (x^2x) - ln (x^2)
Derivative > 2x. x^(2x-1) {which can be simplified to 2x^(2x-1+1)= 2x^2x}/ x^(2x) - 2x/ x^2
= 2x^2x/ x^2x - 2x/ x^2
This one's more complex.
Welcome~
uh-oh seems u neva got wht actually im asking :|
its x(square) this multiplied to (x-1) now get it??
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uh-oh seems u neva got wht actually im asking :|
its x(square) this multiplied to (x-1) now get it??
Yeah, but isn't that what I did earlier? My first post?
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Yeah, but isn't that what I did earlier? My first post?
ooopps my bad, i was reading it rong ur first post...sooorrryyy :-[ and thank youu so mucchh :)
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i can help you with vectors. do you have a specific part of vectors or is it vectors as a whole . so there eqn of a line, using 2 points, 1 directioin vector and a point. point of intersetion . foot of a line . angle between two lines. and for plane there is equn plane . finding eqn using 3 points , using another plane. then there intersection between 2 planes, angle between two planes. and plane and line which consist of angle between line and plane and point of intersection . im sure theres abit more but i cant think of it from the top of my head. pm if you want me to go through a specific one
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i can help you with vectors. do you have a specific part of vectors or is it vectors as a whole . so there eqn of a line, using 2 points, 1 directioin vector and a point. point of intersetion . foot of a line . angle between two lines. and for plane there is equn plane . finding eqn using 3 points , using another plane. then there intersection between 2 planes, angle between two planes. and plane and line which consist of angle between line and plane and point of intersection . im sure theres abit more but i cant think of it from the top of my head. pm if you want me to go through a specific one
*coughs* aheemm ill get back to you, lemme hit my books n see if sumthing gets inside.
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ooopps my bad, i was reading it rong ur first post...sooorrryyy :-[ and thank youu so mucchh :)
No worries. And you're welcome. Lucky, today I have some time to help you.
I see you are a good fan of 'Another Cinderella story'. :)
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sure ;D
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Q2) Find the integral of
root of (4-x^2) ; use substitution x=2sintheta
im stuck half way :\ hellpp please =)
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Q2) Find the integral of
root of (4-x^2) ; use substitution x=2sintheta
im stuck half way :\ hellpp please =)
I'll use @ for theta.
x = 2 sin 2
x^2 = 4 sin^2 @
/ for root.
/ (4 - x^2) = / [4(1-sin^2@)]
Using identity sin^2@ + cos^2@ = 1,
/ [4(1-sin^2@)] = / 4 cos^2@
= 2 cos @
Now integrate.
Differentiation of sin@ > cos@,
Integration of cos@ > sin@.
Integrate 2 cos@ > 2 sin@.
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oh ohkay i got it, was skippin one step, Thank You..
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Q3)Integral of (50-m)^-2??
the answer given is (50-m)^-1 buh im gettin -(50-m)^-1, where am i rong?:S
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You are ignoring the - in -m
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You are ignoring the - in -m
ohh so we mutiply -1 in the denominator with -1 to get +1? ohkk...Thank You astar=)
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is ok.
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Q4)Two planes have equation x+2y-2z=2 and 2x-3y+6z=3. The planes intersect in the straight line L. Find a vector equtaion for line L.
ok so i just know to get the vector equation of a line we use this>> r=a+$p, where a is the position vector, $ is a scaler and p is direction vector, after that how to get all that i dunno....please help...=\
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so to find the direction vector you cross multiply the normals using matrices rules. and to find the point on the line you do simultaneous equation using the two plane quations but thats where it gets tricky. the trick is to sub in a value for x y or z which will give zero thus only one unknown is left. i rather not type the answer here cause its difficult to type and i dont know how to scan in the work sheet into forum ???hope it my methods helps
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so to find the direction vector you cross multiply the normals using matrices rules. and to find the point on the line you do simultaneous equation using the two plane quations but thats where it gets tricky. the trick is to sub in a value for x y or z which will give zero thus only one unknown is left. i rather not type the answer here cause its difficult to type and i dont know how to scan in the work sheet into forum ???hope it my methods helps
u scan ur worksheet and attach to your post cz i aint gettin what u said to do for the point on the line =\ to attach click on the additional options...
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hahaa ok i think i failed at the scanning thing but il try it here .
(a)x+2y-2z=2 and (b)2x-3y+6z=3
so point on line would be . so simultaneously solve both of them . (trick) sube 0 into one of them . i choose z
when z=0
(a)x+2y=2 (b) 2x-3y=3
now its easy so you can solve for x and y. sub back into eqn and walla you get the point ahh haha sound so nerdy
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hey thnxxx i got it =)
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awesome ;D
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Q5)How to sketch the graph of y=secx, for 0<=x<=2pi
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Q5)How to sketch the graph of y=secx, for 0<=x<=2pi
check this Trig graph (http://www.intmath.com/Trigonometric-graphs/4_Graphs-tangent-cotangent-secant-cosecant.php)
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check this Trig graph (http://www.intmath.com/Trigonometric-graphs/4_Graphs-tangent-cotangent-secant-cosecant.php)
this stuff is just soo cool n helpful!! im really thankful to you!! ;D
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Q1 part 1 how to do it? :S
http://www.srepapmaxeeeerf.org/A%20Level/Maths/CIE/2009%20Jun/9709_s09_qp_6.pdf
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i did it on pakistanis hea...
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Q1 part 1 how to do it? :S
http://www.srepapmaxeeeerf.org/A%20Level/Maths/CIE/2009%20Jun/9709_s09_qp_6.pdf
225/900=0.25(contains mor dan 1002)
1-0.25=0.75
Q(x)=0.75
x=0.6745
(1002-mu)/8=0.6745
mu=996.6
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i did it on pakistanis hea...
Thanks got it=)
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225/900=0.25(contains mor dan 1002)
1-0.25=0.75
Q(x)=0.75
x=0.6745
(1002-mu)/8=0.6745
mu=996.6
Thanks buddy, Q3 (i), in ms why have they taken 0.84?? please explain
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http://www.srepapmaxeeeerf.org/A%20Level/Maths/CIE/2009%20Jun/9709_s09_ms_6.pdf
here this is the mark scheme
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Thanks buddy, Q3 (i), in ms why have they taken 0.84?? please explain
dey hve asked 4 probability of busses which is 16%, so da other vehicles r 100-16=84% which is 0.84
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dey hve asked 4 probability of busses which is 16%, so da other vehicles r 100-16=84% which is 0.84
k...Q4 (iii) ???
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BBBB"T(odd 1 out)"TTT
so 4P4*3P3*2
*2 because it cud b TTTTBBBB as well..
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By the way how come u hve doubts in S1, because u helped me in P3 questions which r tough :o
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By the way how come u hve doubts in S1, because u helped me in P3 questions which r tough :o
because this is the only component of math i suck at :'( im so freaked out for tom's exam...=\
and By the way thaaank yoouuu soo much.....
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No need 2 worry,u'll do gud, after all this component comes 2 only 20% . :)
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Q7 part (i) and (ii) how to do??
http://www.srepapmaxeeeerf.org/A%20Level/Maths/CIE/2007%20Nov/9709_w07_qp_6.pdf
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Q7 part (i) and (ii) how to do??
http://www.srepapmaxeeeerf.org/A%20Level/Maths/CIE/2007%20Nov/9709_w07_qp_6.pdf
ooopps i got it...was not reading the question properly =\
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could some 1 plz explain me question 7iii) in WO3 pure 3 maths plz thank u :)
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Can anyone help me with these math questions (past years CIE P3)
M/J 08 (5 ii)
M/J 09 (6 ii and iii)
O/N 09 3/1 7(iv)
please show all the working of algebra working clearly
thank ;D
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HORRIBLE STATISTICS PAPER!!! :'(
GD LUCK 4 PURE !!!
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w03 7iii
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HORRIBLE STATISTICS PAPER!!! :'(
GD LUCK 4 PURE !!!
How waz ur P1
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M/J 08 (5 ii)
M/J 09 (6 ii and iii)
O/N 09 3/1 7(iv)
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thanks for the help ;D
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HORRIBLE STATISTICS PAPER!!! :'(
GD LUCK 4 PURE !!!
soo trueee =( anyways GOoOOod NewS!!!
my sir said dont worry about this paper, however you do, if u get around 65 in pure math 3 ull end up with an overall A , i cant be any more happier ;D
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soo trueee =( anyways GOoOOod NewS!!!
my sir said dont worry about this paper, however you do, if u get around 65 in pure math 3 ull end up with an overall A , i cant be any more happier ;D
Easier said, dan done :(
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soo trueee =( anyways GOoOOod NewS!!!
my sir said dont worry about this paper, however you do, if u get around 65 in pure math 3 ull end up with an overall A , i cant be any more happier ;D
and what do you need to get in P1 to get a good chance of a A overall
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Thank u astarmathsandphysics but can u plz explain why cant we do 180 - tan^-1 (2/1) like y does this give the wrong answer it gives me 116 but y ? i hope u understand wht i meant :-\
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and what do you need to get in P1 to get a good chance of a A overall
If you did today's S1 >:(
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oh cool i got it thank u astar :D
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Easier said, dan done :(
nope, p3 is manageable =)
anything but stats -__-
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and what do you need to get in P1 to get a good chance of a A overall
65 plus too...im hopin for 75 By the way in p1 it was good...May Allah make tht happen...
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If you did today's S1 >:(
yea i swear todays S1 was just sooo horrible >:(
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yea i swear todays S1 was just sooo horrible >:(
i have business tomorrow and my hand , legs hurt so much.
JESUS!
i feel like crying
(not for S1 that went well Alhamdullilah but for tomorrow's exam)
Not able to find strength
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Is it dat mostly girls find stats difficult.. :P
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Is it dat mostly girls find stats difficult.. :P
apparently
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ermm anyone has the workings for CIE Pure Maths 3
may/june09 paper
oct/nov varient 31 and 32 2009 papers.
pleaseeeeeeeeee. i don't seem uncerstand them.
thanks!!!
am doing last min crammings....thank u very very much in advance. my p3 will be in 10hrs time..
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ermm anyone has the workings for CIE Pure Maths 3
may/june09 paper
oct/nov varient 31 and 32 2009 papers.
pleaseeeeeeeeee. i don't seem uncerstand them.
thanks!!!
am doing last min crammings....thank u very very much in advance. my p3 will be in 10hrs time..
ummm if you tell me what specific questions you don't get i'll try to help? i'm not gonna do three whole papers for you though -_-
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ummm if you tell me what specific questions you don't get i'll try to help? i'm not gonna do three whole papers for you though -_-
ahh. thanks for the offer!! u're so kind.
mayjune 2009
Q8(ii) Q10
oct/nov2009 variant 31
Q1 Q5(ii) Q7(iv) Q9 Q10
oct/nov2009 variant 32
Q2(i) Q4 Q6 Q9(iii) and Q10
thank u!!!
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ahh. thanks for the offer!! u're so kind.
mayjune 2009
Q8(ii) Q10
oct/nov2009 variant 31
Q1 Q5(ii) Q7(iv) Q9 Q10
oct/nov2009 variant 32
Q2(i) Q4 Q6 Q9(iii) and Q10
thank u!!!
um here's the first one http://i45.tinypic.com/28lxfds.jpg
i have to go study physics now though so i don't have time to do them all atm :-\
i'll try to do them later if no one else has.
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um here's the first one http://i45.tinypic.com/28lxfds.jpg
i have to go study physics now though so i don't have time to do them all atm :-\
i'll try to do them later if no one else has.
alrite! thank u once again... :D
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cld some1 plz help me in W07 10i) only the first part with explanation plz thank u
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hey could some one please help me with
j09 Q6(ii)
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Why don't you people post the link to the papers directly??
Whenever I have some free time, come here, and keep wondering which papers you are talking about. :P
So, please, it's a request: state your papers clearly, along with your exams board.