Question

已知点P(x,y)满足方程x^2+y^2-4x-4y+7=0,求(y-1)/(x+2)的取值范围

Answer 1

x^2+y^2-4x-4y+7=0

(x-2)^2+(y-2)^2=1

故：(x-2)^2≤1 1≤x≤3 3≤x+2≤5

(y-2)^2≤1 1≤y≤3 0≤y-1≤2

所以：(y-1)/(x+2)的取值范围：：0≤(y-1)/(x+2)≤2/3