Question

f(x)=arctan(7x) then f'(1)=?

Answer 1

Use chain rule. Note that \(\dfrac{d}{dx}\tan^{-1}x = \dfrac{1}{1+x^2}\)

Answer 2

Once you find f'(x), plug in 1.

Answer 3

Of okay, the format of the question confused me, Thanks(:

Answer 4

No problem.