令x = sinz,dx = cosz dz
∫ 1/[x√(1 - x²)] dx
= ∫ 1/(sinz * cosz) * cosz dz
= ∫ cscz dz
= ln(cscz - cotz) + C
= ln[1/sinz - √(csc²z - 1)] + C
= ln[1/sinz - √(1 - sin²z)/sinz] + C
= ln[1/x - √(1 - x²)/x] + C
= ln[1 - √(1 - x²)] - ln(x) + C
对数后面要绝对号,你知道吧
令x = sinz,dx = cosz dz
∫ 1/[x√(1 - x²)] dx
= ∫ 1/(sinz * cosz) * cosz dz
= ∫ cscz dz
= ln(cscz - cotz) + C
= ln[1/sinz - √(csc²z - 1)] + C
= ln[1/sinz - √(1 - sin²z)/sinz] + C
= ln[1/x - √(1 - x²)/x] + C
= ln[1 - √(1 - x²)] - ln(x) + C
对数后面要绝对号,你知道吧