Contact us
Choose a category below so we can get back to you as quickly as possible.
a决定開口方向 b决定橫向的位置(其實是-a/(2b)) c决定抛物線在y軸的截距(即與y軸交點座標)
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.