# Math Help - basic calc questions

1. ## basic calc questions

Hi, I've got had 28 questions to do for homework over the weekend (yup, my maths teacher is the devil himself), I've done most of it but there's a few questions that I can't for the life of me get.

Was just wondering if anyone could have a look at some of these and see if they can help out, I'm not asking for anyone to do all of it, just maybe if you can help out on a question or two. Most of you will find it very easy anyway.

Here you go

http://i26.tinypic.com/2zgwvab.jpg
http://i27.tinypic.com/sg2t6x.jpg - for 15a I got b to be 6 but can't do b
http://i29.tinypic.com/av2zhf.jpg

Thank you very much, any help whatsoever is very much appreciated.

2. Originally Posted by jumba
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Here you go
...
http://i27.tinypic.com/sg2t6x.jpg - for 15a I got b to be 6 but can't do b
...

Thank you very much, any help whatsoever is very much appreciated.
To 15 a) Plug in x=-2 into the equation of the function. Then b = f(-2).

Keep in mind that $3(-2)^3 = -24$ and that $-(-2)^2 = -4$. You'll find that your calculated value of b must be wrong.

To 15 b) The function f is increasing in P if the gradient of f in P is positive. Therefore determine the first derivation of f and plug in x = -2. If f'(-2) > 0 then the statement is true.

EDIT: Could you please indicate which of the questions are not clear to you?

3. Thanks, I'll see what I can do.

It's all the questions I posted in the picture that I'm having trouble with.