求瑕积分∫dx⼀ (√x(x+1)) ,[0,1]

2025-05-23 23:10:58
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回答1:

∫[0--->1] √[x/(1-x)] dx
这是一个瑕积分,根据瑕积分的定义
=lim [ε--->0+] ∫[0--->1-ε] √[x/(1-x)] dx
令x/(1-x)=t²,则x=t²/(1+t²),dx=2t/(1+t²)²dt,t:0---->√(1/ε-1)
=lim [ε--->0+] ∫[0---->√(1/ε-1)] t*2t/(1+t²)²dt
=lim [ε--->0+] ∫[0---->√(1/ε-1)] 2t²/(1+t²)²dt