AQA Mathematics Module 5 Paper 2H (Calc) Unofficial Answers (10/06/2011)

Very last question:
Square of length 3y-2x and rectangle of lengths 3y+2x and 2x have equal area. Prove y is a multiple of x.
(3y-2x)(3y-2x)=2x(3y+2x)
9y2-12xy+4x2=6xy+4x2
9y2=18xy
9y=18x
Therefore y=2x

(edited 12 years ago)

Reply 42

To re-arrange trapezium formula:

A = 1/2(a+b)h
== A/h = 1/2(a+b)
== (-1/2)b = (1/2)a - A/h
== -b = a - (2A)/h
== b = -a + (2A)/h

Reply 43

username807367

Original post by FO12DY

Can you remember the details?

Areas were equal, but what were the side lengths?

I think one of rectangles was 2x, but I don't remember any others.

I wrote that one on some tracing paper.

The areas of the square and the rectangle are equal. Show that y is a multiple of x

Square side length - (3y-2x)
Rectangle long side length - (3y+2x)
Rectangle short length - 2x

(edited 12 years ago)

Reply 44

Original post by RedUnited

Very last question:
Square of length 3y-2x and rectangle of lengths 3y+2x and 2x have equal area. Prove y is a multiple of x.
(3y-2x)squared=2x(3y+2x)
9y2-12xy+4x2=6xy+4x2
9y2=18xy
9y=18x
Therefore y=2x

Ah, thanks Red, was missing those details :wink:

Linked from first post.

Reply 45

mastadon

y=2x
I got lucky, i randomly subbed in y=4 and x=2 and it worked for me. I simplified the formula, subbed these in and they were equal to zero. I believe when you simplified it worked out to be 9y(y-18x)=0. If you sub the two values in you get 0 = 0.

Reply 46

Original post by FO12DY

Ah, thanks Red, was missing those details :wink:

Linked from first post.

No probs, trying to think of any other questions I can remember

Reply 47

Hmm, well we have 14 questions, but there were at least 16 - we have the 15th, and the last one.

Can't remember any others though :/

Reply 48

Have we got the graph and inequality one up? y=3x-1, and then shade the region that satisfies the inequality y<3x-1

Reply 49

the cosine values has to be between 180n and 360 degrees :smile:

Reply 50

(1/3)x - 4 = 1/2
for this one i got -10.5 i think :s

Reply 51

15c you had to use the quadratic equation didn't you?
which got you 11 and 14.9...

Reply 52

west28

anychance we can actually put all qs and answers in one bloody post! :P

Reply 53

i think there were 19 questions overall... could be wrong but i remember seeing that question number :P

Reply 54

blahblahh

should pi(a+b) be a length? because they're multiplying each other?

Reply 55

blahblahh

Original post by Wisdom

(1/3)x - 4 = 1/2
for this one i got -10.5 i think :s

I got that aswell :smile:

Reply 56

Original post by Wisdom

15c you had to use the quadratic equation didn't you?
which got you 11 and 14.9...

Wasn't it -1 and 4.25? It was given in the question that one of the solutions was -1 or am I talking about the wrong question

Reply 57

MissMoo

Can anyone remember the marks for the questions?

Reply 58