用公式:
1+1/(1+2)+1/(1+2+3)+1/(1+2+3+4)+……+1/(1+2+3……+n) = 2n/(1+n)
题中的n=11
所以1/1+1/1+2+1/1+2+3+1/1+2+3+4+··1/1+2+3+···11
=2x11/(1+11)
=264
用公式:
1+1/(1+2)+1/(1+2+3)+1/(1+2+3+4)+……+1/(1+2+3……+n) = 2n/(1+n)
题中的n=11
所以1/1+1/1+2+1/1+2+3+1/1+2+3+4+··1/1+2+3+···11
=2x11/(1+11)
=264