√x=t,x=t^2,dx=2tdt
∫(0~4) e^(√x)dx
=2∫(0,2) e^t*tdt
=2∫(0,2) td(e^t)
=2[te^t|(0,2)-∫(0,2) e^tdxt]
=2[2e²-(e²-1)]
=2(e²+1)