Maths help transformation

Yazomi

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Is there an error on the mark scheme?
For the answer iv)

Reply 1

ghostwalker

Original post by Yazomi

Is there an error on the mark scheme?
For the answer iv)

No.

Compare q(x) with g(x) with regard to the constant - it's gone from +4 to +1; change is -3 in the y-direction.

(edited 2 years ago)

Reply 2

RDKGames

Study Forum Helper

Original post by Yazomi

Is there an error on the mark scheme?
For the answer iv)

Nope.

If q(x)=x^2+4 then q(x-3)-3 = (x-3)^2 + 1 which is g(x)

Reply 3

Yazomi

Original post by ghostwalker

No.

Compare q(x) with g(x) with regard to the constant - it's gone from +4 to +1; change is -3 in the y-direction.

Wait why is q(x) being compared instead of f(x)?

Reply 4

Yazomi

Original post by RDKGames

Nope.

If q(x)=x^2+4 then q(x-3)-3 = (x-3)^2 + 1 which is g(x)

I thought the question was asking for a comparison of f(x) rather than q(x)?

Reply 5

RDKGames

Study Forum Helper

Original post by Yazomi

I thought the question was asking for a comparison of f(x) rather than q(x)?

Not sure what you mean.

You want to solve f(x)=g(x) but using the solution to p(x)=q(x). So you rewrite f,g in terms of p,q.

Reply 6

ghostwalker

Original post by Yazomi

Wait why is q(x) being compared instead of f(x)?

You compare q(x) with g(x) to find how q(x) has been transformed.

You compare p(x) with f(x) to find how p(x) has been transformed.

And it turns out they've both been transformed by the same amount (3,-3)

Reply 7

Yazomi

Original post by ghostwalker

Wait how do you know which ones to compare is it just because q(x) and g(x) highest power is x^3

And p(x) and f(x) highest power is x^2?

Original post by RDKGames

Not sure what you mean.

You want to solve f(x)=g(x) but using the solution to p(x)=q(x). So you rewrite f,g in terms of p,q.

(edited 2 years ago)

Reply 8

RDKGames

Study Forum Helper

Original post by Yazomi

Wait how do you know which ones to compare is it just because q(x) and g(x) highest power is x^3

And p(x) and f(x) highest power is x^2?

Yes . Can’t compare a cubic to a quadratic ... this is a nonlinear transformation.

Reply 9

Yazomi

Original post by RDKGames

Yes . Can’t compare a cubic to a quadratic ... this is a nonlinear transformation.

Ahhh this makes sense now thank you so much :smile:

Reply 10

ghostwalker

Original post by Yazomi

Ahhh this makes sense now thank you so much :smile:

To sum up:

p and q are two functions that intersect at a certain point.

p is transformed to f, and q is transformed to g

By comparing p and f we find what the transformation is from one to the other.
By comparing q and g we find what that transformation is.

They are the same; both graphs have been shifted in an identical manner, and so their point of intersection will have been shifted in the same manner.

Reply 11

the bear

the intersection of p(x) and q(x) is at (2,8)

the intersection of p(x-3)-3 and q(x-3)-3 will be the point (2,8) with a translation of 3 right and 3 down.