已知实数XY 满足方程X^2+Y^2+4X+3=0 则S=(X-1)^2+(Y+3)^2的取值范围

已知实数XY 满足方程X^2+Y^2+4X+3=0 则S=(X-1)^2+(Y+3)^2的取值范围
已知实数XY 满足方程X^2+Y^2+4X+3=0 则S=(X-1)^2+(Y+3)^2的取值范围

已知实数XY 满足方程X^2+Y^2+4X+3=0 则S=(X-1)^2+(Y+3)^2的取值范围
x^2+y^2+4x+3=0 ==> (x+2)^2+y^2=1,故可设x=-2+cost,y=sint;故S=(x-1)^2+(y+3)^2=(-3+cost)^2+(3+sint)^2=16+(6根号2)sin(x-丌/4).因-1=