Calc-please help

Question

Let f(x) = (ln x)^2

f’(x)=

f’(e^4)

Answer 1

The function f(x)=(lnx)(lnx) and so in order to find its derivative you can use the product rule which implies that

f'(x)=(lnx)'(lnx)+(lnx)(lnx)'=2(lnx)(lnx)'=2(lnx)/x. For the value f'(e^4)=2(ln(e^4))/(e^4)=8/(e^4).