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∫x∧3arcsinx/√(1-x∧2)

题目详情
∫x∧3arcsinx/√(1-x∧2)
▼优质解答
答案和解析
设x=sint
√(1-x^2)=cost dx=costdt
则原式化为
∫(sint)^3arcsin(sint) *cost dt/cost
=∫t(sint)^3dt
=-∫t(sint)^2dcost
=-∫t(1-(cost)^2 dcost
=-∫tdcost+∫t(cost)^2dcost
=-tcost+∫costdt+1/3∫td(cost)^3
=-tcost+sint+1/3t(cost)^3-1/3∫(cost)^3dt
=-tcost+sint +1/3t(cost)^3-1/3∫(cost)^2dsint
=-tcost+sint +1/3t(cost)^3-1/3∫(1-(sint)^2)dsint
=-tcost+sint +1/3t(cost)^3-1/3∫dsint+1/3∫(sint)^2dsint
=-tcost+sint +1/3t(cost)^3-sint /3+(sint)^3/6 +C 剩下的自已去化简了