解
3.f(x)=(2x+1)e^xf'(x)=(2x+1)'e^x+(2x+1)(e^x)'=2e^x+(2x+1)e^x=(2x+3)e^xf'(0)=(2·0+3)·e⁰=3选C4.f'(x)=(cosx)'=-sinxf'(π/2)=-sin(π/2)=-1tanα=-1α=3π/4切线的倾斜角为3π/4
