求函数y=(1-x２)/(1+x２)的值域请详细写名过程,谢谢
解：y=(1-x^2)/(1+x^2)y(1+x^2)=(1-x^2)x^2=(1-y)/(1+y)......y不等于－１x^2=(1-y)/(1+y）=0,-1
