设f(x)=(sin2xcos3x+cos2xsin3x)lnx,则f'(π/2)=
问题描述:
设f(x)=(sin2xcos3x+cos2xsin3x)lnx,则f'(π/2)=
答
f(x)=(sin2xcos3x+cos2xsin3x)lnx=sin(5x)lnx
f'(x)=5cos(5x)lnx+sin(5x)/x;
代入得2/π