Contact us
Choose a category below so we can get back to you as quickly as possible.
不一定啊與de有關x^2+y^2+Dx+Ey+F=0 (x+D/2)^2 +(y+E/2)^2 = -F +D/4 + E/4 -F +D/4 + E/4 = r^2 >0
We and our partners use cookies and other technologies to analyze traffic and optimize your experience. View more info and control your cookies settings at any time in our Cookies Policy.