lxlixuan
幼苗
共回答了17个问题采纳率:94.1% 举报
∫ (x-arctanx)/(1+x²) dx
= ∫ x/(1+x²) dx - ∫ arctanx/(1+x²) dx
= (1/2)∫ d(x²+1)/(1+x²) - ∫ arctanx d(arctanx)
= (1/2)ln(1+x²) - (1/2)(arctanx)² + C
L = ∫ e^x * sin(x/2) dx
= 2∫ e^x * sin(x/2) d(x/2)
= -2∫ e^x dcos(x/2)
= -2(e^x)cos(x/2) + 2∫ cos(x/2) d(e^x)
1年前
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