Contact us
Choose a category below so we can get back to you as quickly as possible.
原式=1*5+2+2*5+2+…+n*5+2 =5*(1+2+3+…+n)+2*n =5*(1+n)*n/2+2n =2.5n^2+2.5n+2n =2.5n^2(n平方)+4.5n
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.