计算下列定积分: ∫上限1下限0(xe^x)dx; ∫上限1e下限0xlnxdx;求过程!!!

2024-12-04 01:29:57
推荐回答(1个)
回答1:

∫(0→1) xe^x dx = ∫(0→1) x d(e^x)
= xe^x - ∫(0→1) e^x dx
= [(1)e^(1) - (0)e^(0)] - e^x
= e - [e^(1) - e^(0)]
= e - e + 1
= 1

∫(0→e) xlnx dx = ∫(0→e) lnx d(x²/2)
= (1/2)x²lnx - (1/2)∫(0→e) x² d(lnx)
= [(1/2)(e²)ln(e) - (1/2)(0)] - (1/2)∫(0→e) x dx
= (1/2)e² - (1/2)(x²/2)
= (1/2)e² - (1/4)(e² - 0)
= (1/4)e²