If f(x)=log2(x)f(x) = \log_2(x)f(x)=log2(x), what is f′(x)f'(x)f′(x)?
1/x1/x1/x
1/(xln2)1/(x \ln 2)1/(xln2)
ln(2)/x\ln(2)/xln(2)/x
1/(2x)1/(2x)1/(2x)