1/(3*5)+1/(5*7)+1/(7*9)+…1/(103*105)
1/(3*5)+1/(5*7)+1/(7*9)+…1/(103*105)
1×3×5+3×5×7+5×7×9+…+101×103×105=?
3*1/5+5*1/7+7*1/9+……+103*1/105的简便算法
101+103+105+107+...+1997+1999=?利用1+3+5+7+9+...+(2n-1)=(n+1)&
-9*(-11)-12*(-8) (1/3-5/7-2/5)*105
计算 (1)(1-105×(3/1-7/3-7/5-5/2)
1、1+3+5+7+.+(2n-1)+(2n+1)+(2n+3)= 103+105+107+.+2007+2009=
1+3+5+7+9+……+101+103+105=?
1/(1*3*5)+1/(3*5*7)+1/(5*7*9)+1/(7*9*11)+1/(9*11*13+)1/(11*1
1+3+5+7+``````+(2n-1)+(2n+1)+(2n+3)和103+105+107+······+2003+
1-3+5-7+9-11+…97+(-99)
已知(1/3-1/5)×1/2=1/15,(1/5-1/7) ×1/2,(1/7-1/9)1/2+1/63……