1/(1×3×5)+1/(3×5×7)+1/(5×7×9)+1/(7×9×11)+1/(9×11×13)的简便算法

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1/(1×3×5)+1/(3×5×7)+1/(5×7×9)+1/(7×9×11)+1/(9×11×13)的简便算法
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1/(1×3×5)+1/(3×5×7)+1/(5×7×9)+1/(7×9×11)+1/(9×11×13)的简便算法
1/(1×3×5)+1/(3×5×7)+1/(5×7×9)+1/(7×9×11)+1/(9×11×13)的简便算法

1/(1×3×5)+1/(3×5×7)+1/(5×7×9)+1/(7×9×11)+1/(9×11×13)的简便算法
1/(1×3×5)+1/(3×5×7)+1/(5×7×9)+1/(7×9×11)+1/(9×11×13)
=(1/2)*[1/(1*3)-1/(3*5)]+(1/2)*[1/(3*5)-1/(5*7)]+...+(1/2)*[1/(9*11)-1/(11*13)]
=(1/2)*[1/(1*3)-1/(11*13)]
=(1/2)*(140/429)
=70/429.

简便运算 (1+1/3+1/5+1/7)*(1/3+1/5+1/7+1/9)-(1+1/3+1/5+1/7+1/7+1/9)*(1/3+1/5+1/7) 算术题,(1+1/3+1/5+1/7)×(1/3+1/5+1/7+1/9)-(1+1/3+1/5+1/7+1/9)×(1/3+1/5+1/7) 数奥题(1+1/3+1/5+1/7)*(1/3+1/5+1/7+1/9)-(1+1/3+1/5+1/7+1/9)*(1/3+1/5+1/7)求(1+1/3+1/5+1/7)*(1/3+1/5+1/7+1/9)-(1+1/3+1/5+1/7+1/9)*(1/3+1/5+1/7)的简便算法要求: 两题算24点.1、(7、7、3、3)2、(5、5、5、1) (1-3/2*4)*(1-3/3*5)*...*(1-3/7*9) 计算 (1)(1-105×(3/1-7/3-7/5-5/2)怎么算的 式子 105×(3/1-7/3-7/5-5/2) 简算 (2+3+1/5)+(2/3-5/17)-(1/5+12/7) 1/1*3=1/2(1-1/3)1/3*5=1/2(1/3-1/5)1/5*7=1/2(1/5-1/7).1/17*19=1/2(1/17-1/19)所以1/1*3+1/3*5+1/5*7+.1/17*19=1/2(1-1/3)+1/2(1/3+1/5)+1/2(1/5-1/7)+.1/2(1/17-1/19)=1/2(1-1/3+1/3-1/5+1/5-1/7+1/7.+1/17-1/19)=1/2(1-1/1 (-5)*(+7 1/3)+(+7)*(-7 1/3)-(+12)*7 1/3 简便方法计算 一道数学题:1/(1*3) + 1/(3*5) +1/(5*7)+ …… 1/(2009*2011)= 1/(1*3) + 1/(3*5) +1/(5*7)+ …… 1/(2009*2011)= 数学题 1/(1*3)+1/(3*5)+1/(5*7)+.+1/(2007*2009) 计算(1/1*3)+(1/3*5)+(1/5*7)+……+(1/19*21) 】 1/(1*3)+1/(3*5)+1/(5*7)+.+1/(49+51)的简便运算 1/(1×3×5)+1/(3×5×7)+1/(5×7×9)+1/(7×9×11)+...+1/(2001×2003×2005)=? 1+3+5= 1+3+5+7= 1+3+5+7+.+(2n-1)= 1/(1*3*5)+1/(3*5*7)+1/(5*7*9)+1/(7*9*11).+(25*27*29) 【(1+1/7)-(-3)+(-1/5)】/(-1/105) 1/(1*3)+1/(3*5)+1/(5*7)+1/(7*9)...1/(199*201)=?