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积分下限为2,上限为根号2的定积分∫[(1)/(x√(x^(2)-1))]dx

来源:学生作业帮 编辑:作业帮 分类:数学作业 时间:2024/05/21 12:57:28
积分下限为2,上限为根号2的定积分∫[(1)/(x√(x^(2)-1))]dx
设x=1/cost t=arc cos(1/x)
dx=(sint/cos²t)dt
x*√(x²-1)=(1/cost)*sint/cost=sint/cos²t
所以∫[(1)/(x√(x^(2)-1))]dx
=∫(sint/cos²t)*/(sint/cos²t)*dt
=∫dt
=t
=arc cos(1/x) I(2,√2)
=arc cos(√2/2)-arc cos(1/2)
= π/4-π/3
=-π/12