1/3*7+ 1/7/11+1/11*15+.+1/55*59

问题描述:

1/3*7+ 1/7/11+1/11*15+.+1/55*59

1/3*7+ 1/7*11+1/11*15+.+1/55*59=1/4*(1/3-1/7)+1/4*(1/7-1/11)+1/4*(1/11-1/15)+.+1/4*(1/55-1/59)=1/4*(1/3-1/7+1/7-1/11+1/11-1/15+.+1/55-1/59)=1/4*(1/3-1/59)=1/4*56/177=14/177