求不定积分dx⼀根号x(1-x)

2024-11-19 20:23:38
推荐回答(1个)
回答1:

令(1-x)/x=t^2,则:1-x=xt^2,∴(1+t^2)x=1,∴x=1/(1+t^2),
∴dx=[2t/(1+t^2)^2]dt.
∴∫{1/√[x(1-x)]}dx
=∫{[(1-x)+x]/√[x(1-x)]}dx
=∫{√[(1-x)/x]+√[x/(1-x)]}dx
=∫(t+1/t)[2t/(1+t^2)^2]dt
=2∫[1/(1+t^2)]dt
=2arctant+C
=2arctan{√[(1-x)/x]}+C.