求不定积分∫(dx)/√[(x-a)(b-x)] , (a<x<b)书上写的设我看得都茫然了设 x=acos²t+bsin²t (0<t<π/2),咋设成这样呀?看不懂

问题描述:

求不定积分∫(dx)/√[(x-a)(b-x)] , (a<x<b)
书上写的设我看得都茫然了
设 x=acos²t+bsin²t (0<t<π/2),
咋设成这样呀?看不懂