Question

g(x)=xf(X)的求导?我参考书上写的是g'(x)=xf'(x)+f(x),

Answer 1

g(x)=xf(X)的求导?

求导公式:

(XY)'=X'Y+XY'

所以: g(x)=[xf(x)]'=x'f(x)+x[f(x)]'

=f(x)+xf'(x)