Contact us
Choose a category below so we can get back to you as quickly as possible.
4分之3,2分之1,3分之1,9分之2,(4/27),(8/81) 公比為2/3的等比數列,前一項乘2/3等於後一項.
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.