IGCSE MATHS DOUBTS HERE !!!!

[HUSH1994]

what are ALL the matrix transformations i need for IGCSE?including all reflections,rotation,translation,shear,stretch,enlargement?Please??

[Vin]

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

[WARRIOR]

1.The population of an island increases by 10% each year.After how many years will the original population be doubled.

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.

[elemis]

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.

[WARRIOR]

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 +

[astarmathsandphysics]

no idea

[Galleria]

http://www.xtremepapers.net/CIE/Cambridge%20IGCSE/0580%20-%20Mathematics/0580_w09_ms_22.pdf

Q 21 b .
I don't get it . how is it 960 ?

[elemis]

One moment

[elemis]

The area under a graph is equal to the distance covered.

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

[Deadly_king]

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

[Galleria]

ohhhhhhhhhh lol
now i get it
i kept getting the answer 480 . now i get that we gotta go below too . THANKS !

[elemis]

ohhhhhhhhhh lol
now i get it
i kept getting the answer 480 . now i get that we gotta go below too . THANKS !

No worries

[WARRIOR]

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.

[Deadly_king]

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

[WARRIOR]

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