cho f(x)= logx (x+2) tính f'(x) bằng bao nhiêu a. 0
Giải thích
Đáp án C
f(x)=logx(x+2)=ln(x+2)lnx⇒f'(x)=1x+2lnx-ln(x+2).1xln2x=xlnx-(x+2)ln(x+2)x(x+2)ln2x⇒f'(2)=2ln2-4ln48ln22=-6ln28ln22=-34ln2
Đáp án C
f(x)=logx(x+2)=ln(x+2)lnx⇒f'(x)=1x+2lnx-ln(x+2).1xln2x=xlnx-(x+2)ln(x+2)x(x+2)ln2x⇒f'(2)=2ln2-4ln48ln22=-6ln28ln22=-34ln2