1*5/1+5*9/1+9*13/1+13*17/1+.45*49/1
1/1×5+1/5×9+1/9×13+1/13×17+1/17×21
1*5/1+5*9/1+9*13/1+13*17/1+17*21/1=?
1/5*1/9+1/9*1/13+1/13*1/17+.1/101*1/105
1/1×5+1/5×9+1/9×13+1/13×17+...+1/25×29=
1+5+9+13+17+.+2009=
1,5,9,13,17 的规律
1/1*5+1/5*9+1/9*13+1/13*17+1/17*21= 小学简便运算
1/1×5+1/5×9+1/9×13+1/13×17+1/17×21简便算法
1/(5×9)+1/(9×13)+1/(13×17)+⋯+1/(101×105)
1/5*9+1/9*13+1/13*17+1/21.1/101*105怎么解
1/5×9+1/9×13+1/13×17+……+1/101×105
计算 1/5*9+1/9*13*1/13*17+.+1/101*105=?