合金装备朔风:数学爱好者进来

来源:百度文库 编辑:查人人中国名人网 时间:2024/05/09 02:34:33
计算:1+1/3+1/6+1/10+...+1/36+1/45

1+1/3+1/6+1/10+...+1/36+1/45
=1/2*(1/2+1/6+1/12+...+1/72+1/90)
=1/2*[1/(1*2)+1/(2*3)+1/(3*4)+...+1/(8*9)+1/(9*10)]
=1/2*(1-1/2+1/2-1/3+...+1/8-1/9+1/9-1/10)
=1/2*(1-1/10)
=9/20