x-1=(t+1)/(t-1)-1=2/(t-1)t-1=2/(x-1)t=(x+1)/(x-1)t^2+t+1=(x+1)^2/(x-1)^2+(x+1)/(x-1)+1=(3x^2+1)/(x-1)^2所以t^3-1=(t-1)(t^2+t+1)=[2/(x-1)][(3x^2+1)/(x-1)^2]所以y=2[(x+1)/(x-1)]/[2/(x-1)][(3x^2+1)/(x-1)...