Year 12s: what will be the first way you research your future options? >>

Curves on graphs

razzy02

Hi, im really struggling with this question, please could someone answer with a detailed explanation? :smile:

Thanks! (please see attached image)

Reply 1

KaylaB

Original post by razzy02

Hi, im really struggling with this question, please could someone answer with a detailed explanation? :smile:

Thanks! (please see attached image)

Well, let us know what you've tried already so we know what part you don't understand :h:

Reply 2

junayd1998

Original post by razzy02

Hi, im really struggling with this question, please could someone answer with a detailed explanation? :smile:

Thanks! (please see attached image)

a) y=mx+c where m is the gradient just rearrange. in that form.

Reply 3

KaylaB

Original post by junayd1998

a) y=mx+c where m is the gradient just rearrange. in that form.

This doesn't actually work for this question, this is due to the question to having an

x^{2}

in the equation instead of an

x

like you suggested.

This can actually be seen from the curve itself, it has a changing gradient unlike a straight line. So this means that differentiation is required to find the gradient at a specific point :h:

EDIT: But this specific question doesn't even require the use of calculus. See post below :smile:

(edited 7 years ago)

Reply 4

DFranklin

Original post by KaylaB

This doesn't actually work for this question, this is due to the question to having an

x^{2}

in the equation instead of an

x

like you suggested.Without differentiation: if a (smooth) curve has a maximum/minimum value, the gradient there must be 0.

I don't know the GCSE syllabus well enough to know if this is what they're expecting, but since they say "write down" I think that's what they're after here.

The 2nd part (gradient at x=2) cannot be found like this but the question makes it clear that you're expected to do this by estimation.

I don't think you're supposed to use calculus for this question at all.

Reply 5

KaylaB

Original post by DFranklin

Without differentiation: if a (smooth) curve has a maximum/minimum value, the gradient there must be 0.

I don't know the GCSE syllabus well enough to know if this is what they're expecting, but since they say "write down" I think that's what they're after here.

The 2nd part (gradient at x=2) cannot be found like this but the question makes it clear that you're expected to do this by estimation.

I don't think you're supposed to use calculus for this question at all.