(x-a)²+(y-b)²=r²怎么化成x²y²+Dx+Ey+F=0

问题描述:

(x-a)²+(y-b)²=r²怎么化成x²y²+Dx+Ey+F=0

(x-a)²+(y-b)²=r²
(x^2-2ax+a^2)+(y^2-2by+b^2)=r^2
x^2+y^2-2ax-2by+(a^2+b^2-r^2)=0