作业帮求不定积分∫x^2arcsinx/√(1-x^2)
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求不定积分∫x^2arcsinx/√(1-x^2)
求不定积分∫x^2arcsinx/√(1-x^2)
求不定积分∫x^2arcsinx/√(1-x^2)
换元,t = arcsinx, dx = cost dt
I = ∫ t sin²t dt = (1/2) ∫ t (1﹣cos2t) dt
= (1/4) t² ﹣(t/4)sin2t + (1/4) ∫ sin2t dt
= (1/4) t² ﹣(t/4)sin2t ﹣ (1/8) cos2t + C
= (1/4)arcsin²x ﹣(1/2) x √(1-x²) arcsinx ﹣ (1/8) (1﹣2x²) + C
= (1/4)arcsin²x ﹣(1/2) x √(1-x²) arcsinx + (1/4) x² + C
不对，解法没对
∫x^2arcsinx/√(1-x^2)dx
=∫(x^2-1+1)arcsinx/√(1-x^2)dx
=-∫√(1-x^2)arcsinxdx+∫arcsinx/√(1-x^2)dx
=-x√(1-x^2)arcsinx+∫xd[√(1-x^2)arcsinx]+(1/2)(arcsinx)^2
=-x√(1-x^2)arcsinx+∫xdx-∫x^2arcsi...
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∫x^2arcsinx/√(1-x^2)dx
=∫(x^2-1+1)arcsinx/√(1-x^2)dx
=-∫√(1-x^2)arcsinxdx+∫arcsinx/√(1-x^2)dx
=-x√(1-x^2)arcsinx+∫xd[√(1-x^2)arcsinx]+(1/2)(arcsinx)^2
=-x√(1-x^2)arcsinx+∫xdx-∫x^2arcsinx/√(1-x^2)dx+(1/2)(arcsinx)^2
=(x^2/2)-x√(1-x^2)arcsinx-∫x^2arcsinx/√(1-x^2)dx+(1/2)(arcsinx)^2
移项除以2得：
∫x^2arcsinx/√(1-x^2)dx
=(1/4)[x^2-2x√(1-x^2)arcsinx+(arcsinx)^2]+C
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