x乘以arcsinx的定积分怎么算(积分区间在0-1)?

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x乘以arcsinx的定积分怎么算(积分区间在0-1)?
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x乘以arcsinx的定积分怎么算(积分区间在0-1)?
x乘以arcsinx的定积分怎么算(积分区间在0-1)?

x乘以arcsinx的定积分怎么算(积分区间在0-1)?
∫(0→1)xarcsinxdx
=0.5∫(0→1)arcsinxd(x²)
=0.5x²arcsinx∫(0→1)-0.5∫(0→1)x²d(arcsinx)
=π/4-0.5∫(0→1)x²/根号(1-x²)dx
=π/4-0.5∫(0→1)1/根号(1-x²)dx+0.5∫(0→1)根号(1-x²)dx

这一部分是半径为1的四分之一圆面积
=π/4-0.5arcsinx(0→1)+π/8
=π/4-π/4+π/8
=π/8

也可以这样
∫[0,-1]xarcsinxdx
x=sinu, dx=cosxdx x=0,u=0 x=-1 u=-π/2
=∫[0,-π/2]sinu *ucosudu
=(-1/4)∫[0,-π/2]udcos2u
=(-1/4)ucos2u|[0,-π/2]+(1/4)∫[0,-π/2] cos2udu
=π/8+(1/8)sin2u[0,-π/2]
=π/8