Let f(x)=(lnx)^4

Question

f'(x)=4(ln(x))^3/x

what is f'(e^2)=?

Answer 1

well, geez, just plug in e^2 into f'(x)

f'(e^2) = 4(ln(e^2))^3/e^2
= 4(2)^3/e^2
= 32/e^2

remember
ln(e^u) = u
e^(ln u) = u