Question

g(x) = lnx / (e^x^2 +2) 求导

Answer 1

g(x)=lnx/(e^x^2 +2),

g'(x)=[(lnx)'*(e^x^2+2)-lnx*(e^x^2+2)']/(e^x^2 +2)^2

=[1/x*(e^x^2+2)-lnx*2x*e^x^2]/(e^x^2 +2)^2

=[e^x^2(1-2x^2*lnx)+2]/(e^x^2 +2)^2

这里利用到[f(x)/g(x)]'=[f'(x)g(x)-f(x)g'(x)]/g(x)^2