∫e^√x dx
令u=√x,x=u^2,dx=2u du
原式=2∫u*e^u du=2∫u d(e^u)
=2(u*e^u-∫e^u du),分部积分法
=2u*e^u-2*e^u+C
=2e^u*(u-1)+C
=2(e^√x)(√x-1)+C