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1. (Original post by kiiten)
if you have to determine if a point is maximum of minimum do you use the first or second derivative? Also, how do you know if it is max or min - is it +ve is max?
When the first derivative is zero at a point, that point is a stationary point.

When the second derivative is +ve at that point, the stationary point is a minimum.

When the second derivative is -ve at that point, the stationary point is a maximum.
2. (Original post by Zacken)
When the first derivative is zero at a point, that point is a stationary point.

When the second derivative is +ve at that point, the stationary point is a minimum.

When the second derivative is -ve at that point, the stationary point is a maximum.
Thank you!! - Does that apply for any other point on a curve?
3. (Original post by kiiten)
Thank you!! - Does that apply for any other point on a curve?
What d'you mean by that? It applies to any stationary point on a curve. A maximum or minimum has to be a stationary point.
4. (Original post by Zacken)
What d'you mean by that? It applies to any stationary point on a curve. A maximum or minimum has to be a stationary point.
Oops sorry I forgot that a max/min point has to be stationary. Ignore the question
5. 2 separate cast circle question. Please could someone show me where i went wrong?
Attachment 514715514717
Attached Images

6. (Original post by kiiten)
2 separate cast circle question. Please could someone show me where i went wrong?
Attachment 514715514717
1st one : Try expanding . It's nearly correct.

2nd one : It looks like you haven't performed any . You have used as your angle instead of .
7. (Original post by notnek)
1st one : Try expanding . It's nearly correct.

2nd one : It looks like you haven't performed any . You have used as your angle instead of .
Thanks i got the 2nd one right now - ill try the 1st one later (did i get the +ve and -ve the wrong way round in the bracket?)

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8. (Original post by kiiten)
Thanks i got the 2nd one right now - ill try the 1st one later (did i get the +ve and -ve the wrong way round in the bracket?)

Posted from TSR Mobile
Yes that was the mistake.
9. How would the diagram look for this question?

10. I think this thread has died :'(
11. (Original post by kiiten)
How would the diagram look for this question?

Zacken
12. (Original post by thefatone)
Zacken
The user has posted this in another thread.
13. (Original post by Zacken)
The user has posted this in another thread.
oh i see

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