求不定积分dx/根号x(1-x)

1个回答

  • 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.