约定:∫[a,b]表示[a,b]上的定积分(1)原式=∫[0,π]|sinx-cosx|dx=∫[0,π/4](cosx-sinx)dx+∫[π/4,π](sinx-cosx)dx=(sinx+cosx)|[0,π/4]+(-sinx-cosx)|[π/4,π]=(√2-1)+(1+√2)=2√2(2)原式=∫[-1,1]1dx+∫[1,3]x^2dx=x|[-1,1]+(1/3)x^3|[1,3]=2+(9-1/3)=32/3希望能帮到你!