document.write( "Question 888258: Sum the Series:
\n" ); document.write( "1×2+2×3+3×4+4×5+⋯+2013×2014
\n" ); document.write( "Thank you!
\n" ); document.write( "

Algebra.Com's Answer #537264 by rothauserc(4718)\"\" \"About 
You can put this solution on YOUR website!
This is a quadratic series whose members are given as
\n" ); document.write( " 2 6 12 20 30 ......4054182
\n" ); document.write( " 1 2 3 4 5 2013
\n" ); document.write( "n^2 1 4 9 16 25 4052169
\n" ); document.write( "a member in the geometric sequence is given by
\n" ); document.write( "nth term = n^2 +n
\n" ); document.write( "now we know that the summation of n^2 = n[n+1][2n+1]/6 and
\n" ); document.write( "summation of n is n(n+1)/2
\n" ); document.write( "therefore the sum(S) of the series is
\n" ); document.write( "S = 2013(2014)(2*2013+1)/6 + 2013(2014)/2
\n" ); document.write( "S = 16326190914/6 + 4054182/2
\n" ); document.write( "S = 2721031819 + 2027091
\n" ); document.write( "S = 2723058910
\n" ); document.write( "
\n" ); document.write( "
\n" );