3. f'(x)=3x^2+a f'(1)=3+a=0 a=-3 f'(x)=3x^2-3=0 x=±1 极大值 f(-1)=5 极小值 f(1)=14. 原式=∫(x^(3/2)-x^(1/2))dx=(2/5)x^(5/2)-(2/3)x^(3/2)+C5.原式=π-∫[0,π](1-sin^2(x))dsinx=π-[sinx-sin^3(x)/3]|[0,π]=π
