Cho fx=logxx+2. Tính f ' (2).

Đáp án A f(x)=logx(x+2)=ln(x+2)lnx⇒f'(x)=1x+2lnx-ln(x+2).1x(lnx)2=x.lnx-(x+2)ln(x+2)x(x+2)lnx2⇒f'(2)=2ln2-4ln48ln22=-6ln28ln22=-34ln2

Cho f(x)=logx(x+2) . Tính f'(x) a. f'(2)=-3/4 ln2 B. f'(x)=0