y=(x^1/2)/(x-1)的反函数怎么求?

(x-1)y=√xxy-√x-y=0(√x-y/2)²=y+y²/4√x-y/2=√(y+y²/4)√x=y/2+√(y+y²/4)x=y²/4+y+y²/4+y√(y+y²/4)反函数为y=x²/2+x+x√(x+x²/4)(√x-y/2)²=y+y²/4这一步里的x去哪儿了？展开看看