Question

求f(x)=1/[(x+1)Ln(x+1)]的导数

Answer 1

[1/f(x)]`=[(x+1)ln(x+1)]`

f`(x)/[f(x)的平方]=[xln(x+1)+ln(x+1)]`=ln(x+1)+x/(x+1)+1/(x+1)=ln(x+1)+1

f`(x)=[ln(x+1)+1]f(x)的平方