Question

f(x)=x/tanx, find f'(pi/4) ???

Answer 1

\(\large f(x)=\frac{x}{tanx} \)
\(\large f'(x)=\frac{(tanx)[x]'-(x)[tanx]'}{(tanx)^2} \)
Simplify that then plug in pi/4 into your derivative....

Answer 2

1. 2-2pi

2. (2-pi)/2

3. 1-2pi

4. 1-pi

5. 2-pi

6. (1-pi)/2

7. -pi

8. pi/2

which one?
I can't apply it in... after I did the f'