y=2x-1/x^2+2x+2和y=x-2/x^2-3x+2的值域
问题描述：
y=2x-1/x^2+2x+2和y=x-2/x^2-3x+2的值域
答
y=（2x-1）/（x^2+2x+2）分母x^2+2x+2=（x+1)^2+1＞0y（x^2+2x+2）= 2x-1yx^2+2yx+2y= 2x-1yx^2+2(y-1)x+(2y+1)= 0判别式△=4(y-1)^2-4y(2y+1)=4y^2-8y+4-8y^2-4y=-4y^2-12y+4≥0y^2+3y-1≤0(-3-√13)/2≤y≤(-3+√1...