1/1*2*3+1/2*3*4+1/3*4*5.+1/9*10*11=
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1/1*2*3+1/2*3*4+1/3*4*5.+1/9*10*11=
1/1*2*3+1/2*3*4+1/3*4*5.+1/9*10*11=
1+(1/1+2)+(1/1+2+3)......+(1/1+2+3+....+100) =
1/1*2*3+1/2*3*4+1/3*4*5.+1/9*10*11=
1+(1/1+2)+(1/1+2+3)......+(1/1+2+3+....+100) =
![1/1*2*3+1/2*3*4+1/3*4*5.+1/9*10*11=](/uploads/image/z/3286025-17-5.jpg?t=1%2F1%2A2%2A3%2B1%2F2%2A3%2A4%2B1%2F3%2A4%2A5.%2B1%2F9%2A10%2A11%3D)
1:因为1/(n*(n+1)(n+2))=(1/2)*(1/(n*(n+1))-1/((n+1)(n+2)),所以原式按这样裂项并整理之后=(1/2)*(1/2-1/110)=27/110.
2:1/(1+2+3+.+n)=1/((1/2)*n*(n+1))=2/(n*(n+1))=2*(1/n-1/(n+1)),所以原式=1+2*(1/2-1/3+1/3-1/4+.+1/100-1/101)=1+2*(1/2-1/101)=200/101.
2:1/(1+2+3+.+n)=1/((1/2)*n*(n+1))=2/(n*(n+1))=2*(1/n-1/(n+1)),所以原式=1+2*(1/2-1/3+1/3-1/4+.+1/100-1/101)=1+2*(1/2-1/101)=200/101.
1/1*2*3+1/2*3*4+1/3*4*5.+1/9*10*11=
1*2*3/1+2*3*4/1+...+9*10*11/1怎样简算?
|3/1-2/1|+|4/1-3/1|+|5/1-4/1|+...+|10/1-9/1|=?3Q
计算:1/1*3+1/2*4+1/3*5+...+1/9*11=?
/1/3-1/2/+/1/4-1/3/+/1/5-1/4/+.+/1/10-1/9/
1/1×2+1/2×3+1/3×4+.+1/9×10=
|1-1/2|+|1/2-1/3|+|1/3-1/4|+...|1/9-1/10|
|1-1/2|-|1/2-1/3|-|1/3-1/4|-.-|1/9-1/10|
1/1+(1/1+2)+(1/1+2+3)……+(1/1+2+3+4+5+6+7+8+9+10+11)=
1+2+3+4+5.+1000=?
上面的8,9,10,11判断的1,2,3,4,5.谢谢大家帮忙
4/1*2*3+5/2*3*4+.+11/8*9*10=?