Contact us
Choose a category below so we can get back to you as quickly as possible.
原式=1/2×(1-1/3+1/3-1/5+1/5-1/7+1/7-1/9+1/9-1/11) =1/2×(1-1/11) =5/11
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.