1*3/1+3*5/1+5*7/1+.+2007*2009/1,最好事这样的:1*2/1+2*3/1+...+9*10/1=(1-2/1)+(2/1-3/1)+...+(9/1-10/1)=1-2/1+2/1-3/1+...+9/1-10/1=1-10/1=10/9这只是一个例子.
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![1*3/1+3*5/1+5*7/1+.+2007*2009/1,最好事这样的:1*2/1+2*3/1+...+9*10/1=(1-2/1)+(2/1-3/1)+...+(9/1-10/1)=1-2/1+2/1-3/1+...+9/1-10/1=1-10/1=10/9这只是一个例子.](/uploads/image/z/3579366-30-6.jpg?t=1%2A3%2F1%2B3%2A5%2F1%2B5%2A7%2F1%2B.%2B2007%2A2009%2F1%2C%E6%9C%80%E5%A5%BD%E4%BA%8B%E8%BF%99%E6%A0%B7%E7%9A%84%EF%BC%9A1%2A2%2F1%2B2%2A3%2F1%2B...%2B9%2A10%2F1%3D%EF%BC%881-2%2F1%EF%BC%89%2B%EF%BC%882%2F1-3%2F1%EF%BC%89%2B...%2B%EF%BC%889%2F1-10%2F1%EF%BC%89%3D1-2%2F1%2B2%2F1-3%2F1%2B...%2B9%2F1-10%2F1%3D1-10%2F1%3D10%2F9%E8%BF%99%E5%8F%AA%E6%98%AF%E4%B8%80%E4%B8%AA%E4%BE%8B%E5%AD%90.)
1*3/1+3*5/1+5*7/1+.+2007*2009/1,最好事这样的:1*2/1+2*3/1+...+9*10/1=(1-2/1)+(2/1-3/1)+...+(9/1-10/1)=1-2/1+2/1-3/1+...+9/1-10/1=1-10/1=10/9这只是一个例子.
1*3/1+3*5/1+5*7/1+.+2007*2009/1,
最好事这样的:1*2/1+2*3/1+...+9*10/1
=(1-2/1)+(2/1-3/1)+...+(9/1-10/1)
=1-2/1+2/1-3/1+...+9/1-10/1
=1-10/1
=10/9
这只是一个例子.
1*3/1+3*5/1+5*7/1+.+2007*2009/1,最好事这样的:1*2/1+2*3/1+...+9*10/1=(1-2/1)+(2/1-3/1)+...+(9/1-10/1)=1-2/1+2/1-3/1+...+9/1-10/1=1-10/1=10/9这只是一个例子.
晕,不看你的例子,不知道你分数是倒着写的.就依你倒着来吧.
1*3/1+3*5/1+5*7/1+.+2007*2009/1
=(1-3/1)÷2+(3/1-5/1)÷2+...+(2007/1-2009/1/1)÷2
=(1-2009/1)÷2=2009/1004
原式=1/2*(1/1-1/3+1/3-1/5+...+1/2007-1/2009)
=1/2*(1-1/2009)
=1004/2009
1-3+5-7+...
(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) 简算(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) 简便计算
1/1*3+1/1*3*5+1/1*3*5*7+1/1*3*5*7*9-73/945
(1/3+1/5+1/7)*(1/5+1/7+1/9)-(1/3+1/5+1/7+1/9)*(1/5+1/7)=?
1/3+1/5+1/7+.+1/2n+1
1/1*3*5+1/3*5*7+1/5*7*9.+1/95*97*99
1/1×3+1/3×5+1/5×7+1/7×9.+1/2011×2013
简算:1/1*3+1/3*5+1/5*7+1/7*9+1/9*11
1/1*3+1/3*5+1/5*7+1/7*9+...1/17*19=
计算1/(1×3)+1/(3×5)+1/(5×7)+1/(7×9)+.+1/(19×21)
1/1×3+1/3×5+1/5×7+1/7×9+.+1/2013×2015
1/1*3+1/3*5+1/5*7+1/7*9+.+1/101*103
帮帮忙1/1*3+1/3*5+1/5*7+1/7*9+...1/99*101
1/1*3+1/3*5+1/5*7+1/7*9+1/49*51=
计算:1/1×3+1/3×5+1/5×7+1/7×9``````+1/2001×2003
(1*3)/1+(3*5)/1+(5*7)/1+(7*9)/1+(9*11)/1
1/1*3+1/3*5+1/5*7+1/7*9+1/9*11
(1*3)/1+(3*5)/1+(5*7)/1+(7*9)/1+(9*11)/1