## ConDawg Group Title (2x^2tan(x))/sec(x) find f ' (x) and f ' (3) one year ago one year ago

1. ConDawg

Answer is 2 x (x cos(x)+2 sin(x)), I just don't know how to do it

2. ConDawg

okay I got cha

3. 3psilon

it gets a little messy

4. ConDawg

What do you do after you get the numerator?

5. 3psilon

Actually forget what I said. Just use the quotient rule

6. ConDawg

(4x)(tan(x))-(2x^2)(sec(x^2)) derivative of tan(x) = sec(x)^2

7. ConDawg

is that right for the numerator?

8. 3psilon

$\frac{ \sec(x)(2x^{2}\sec^{2}x+4xtanx)- 2x^{2} \tan(x)\tan(x)\sec(x) }{ \sec^{2}x }$

9. 3psilon

That's when it is in quotient rule form. As I said . it does get messy :/

10. ConDawg

Wow... sorry it took long to reply, the website isn't working well for me.

11. ConDawg

m trying to follow what you got and how you got it with the formula, i'm just learning the quotient rule

12. 3psilon

The quotient rule is low d(high) - high d(low) all over Low low or low^2

13. 3psilon

high is the numerator and low is the denominator when there is a d next to it that means the derivative

14. 3psilon

In this case the d(high) involved the product rule that's why it got so messy

15. ConDawg

okay im following now. Goodness this hard on the head... so first we found out what the numerator is from the product rule, and then we use the quotient rule

16. 3psilon

Just take it one step at a time :) Use the quotient rule for the whole thing. But you'll come across product rule inside it