已知x=a+1分之a-1 y=2a+3分之3a-1 用x表示y

问题描述:

已知x=a+1分之a-1 y=2a+3分之3a-1 用x表示y

因为x=(a-1)/(a+1)xa+x=a-1a-xa=x+1a(1-x)=x+1a=(1+x)/(1-x)y=(3a-1)/(2a+3)2ya+3y=3a-13a-2ya=3y+1a(3-2y)=3y+1a=(3y+1)/(3-2y)所以(1+x)/(1-x)=(3y+1)/(3-2y)(1+x)(3-2y)=(1-x)(3y+1)3(1+x)-2(1+x)y=3(1-x)y+(1-x)...