Question

Find dy/dx if y= tan9x/x^2

Answer 1

All you have to do is derivative tan9x/x². Do you know how to? No?

Answer 2

I thought I did.. and then I did it wrong on the test. I use the product rule but I didnt follow through correctly.

Answer 3

Do you know quotient rule?

Answer 4

Yes, that's what I meant, I tried to do that and I didn't know what to do with the tan9x? I can't use it as a constant or I tried to put it outside like 9tanx and it came out wrong

Answer 5

Well, actually, to derivative the numeration, you have to use chain rule, you know what it is and how to apply it, right?

Answer 6

I know what it is just no how to use it here. Would it be 1 times 9?

Answer 7

For chain rule, we know that \[\frac{d}{dx}f(g(x)) = f'(g(x)) \cdot g'(x)\]Derivative first function and left second function untouched then derivative second function.

Let f(x) be tanx and g(x) be 9x. Do you know what to do next?

Answer 8

No. I don't

Answer 9

First, we derivative tan(9x). We only need to derivative tan and left 9x untouched. Is this clear?

Answer 10

Okay, yes.so then I have that - tan9xtimes 2x

Answer 11

Thank you for your help but at this point I just can't do this.

Answer 12

Don't say you can't, you can do it! Just derivative the numerator first.

Now, what is derivative of tanx?

Answer 13

sec^2x