Question

Find derivative of f(x)= arctan(e^4x)

I know the formula is 1/ (1+x^2), x being the stuff inside tan, but I can't seem to do it right :(

Answer 1

f(x) = arctan(e^4x)
f'(x) = 1/(1 + (e^4x)^2) * e^4 = e^4/(1 + e^8x^2)