Question

实数x,y满足x2+y2+2x-4y+1=0求（1）y／（x-4）的最值（2）√（x2+y2-2x+1）的最值

Answer 1

x^2+Y^2+2X-4Y+1=0

X^2+2X+Y^2-4Y+1=0

X^2+2X-3+(Y-2)^2=0

(X+3)*(X-1)+(Y-2)^2=0

X=-3 Y=2或x=1 y=2

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