55问答网
所有问题
1/1X2X3+1/2X3X4+1/3X4X5+...+1/98X99X100(要过程)
如题所述
举报该问题
其他回答
第1个回答 2013-09-09
1/1x2x3+1/2x3x4+1/3x4x5+--+1/98x99x100
=(1/2)*(1/1*2-1/2*3)+(1/2)*(1/2*3-1/3*4)+...+(1/2)(1/98*99-1/99*100)
=(1/2)*(1/1*2-1/2*2+1/2*3-1/3*4+...+1/98*99-1/99*100)
=(1/2)*(1/2-1/9900)
=(1/2)*(4949/9900)
=4949/19800.
本回答被网友采纳
相似回答
1/
1x2x3+1
/
2x3x4+1
/
3x4x5+.+1
/8x9x10
答:
1/
1x2x3+1
/
2x3x4+1
/
3x4x5+
1/4x5x6+...+1/8x9x10 =1-1/2-1/2(1-1/3)+1/2-1/3-1/2(1/2-1/4)+1/3-1/4-1/2(1/3-1/5)+1/4-1/5-1/2(1/4-1/6
)+.+1
/8-1/9-1/2(1/8-1/10)=1-1/9-1/2(1+1/2-1/9-1/10)=173/360 ...
1/
1x2x3+1
/
2x3x4+1
/
3x4x5+
...+1/8x9x10如何计算方法
答:
则原式=(1/2)[1/(1×2)-1/(9×10)]=(1/2)[(1/2)-1/(90)]=11/45
1/丨
1x
2ⅹ
3+1
/
2x3x4+
……+1/8ⅹ9x10=
答:
1/
1x2x3+1
/
2x3x4+1
/
3x4x5+
1/4x5x6+...+1/8x9x10 =1-1/2-1/2(1-1/3)+1/2-1/3-1/2(1/2-1/4)+1/3-1/4-1/2(1/3-1/5)+1/4-1/5-1/2(1/4-1/6
)+.+1
/8-1/9-1/2(1/8-1/10)=1-1/9-1/2(1+1/2-1/9-1/10)=173/360 ...
1/
1x2x3+1
/
2x3x4+1
/
3x4x5+1
/4x5x6
+.+1
/8x9x10 等于多少?急!
答:
请1/
1x2x3+1
/
2x3x4+1
/
3x4x5+1
/4x5x6= =1/2×(1/1×2-1/2×3+1/2×3-1/3×4+1/3×4-1/4×5+1/4×5-1/5×6) =1/2×(1/1×2-1/5×6) =7/30 1/1x2x3+1/2x3x4+1/3x4x5+...+1/9x10x11= 1/n(n
+1)(
n+2)=1/2*[1/n-2/(n+
1)+1
/(n+...
1/
1X2X3+1
/
2X3X4+1
/
3X4X5+
...+1/
98X99X100(要过程)
答:
1/
1x2x3+1
/
2x3x4+1
/
3x4x5+
--+1/
98x99x100
=(1/2)*(1/1*2-1/2*3)+(1/2)*(1/2*3-1/3*4)+...+(1/2
)(1
/98*99-1/99*100)=(1/2)*(1/1*2-1/2*2+1/2*3-1/3*4+...+1/98*99-1/99*100)=(1/2)*(1/2-1/9900)=(1/2)*(4949/9900)=4949/19800.
大家正在搜
X1X3X5区别
D(2X-3Y)
AX=2X+A,求X
D(2X-Y)
买X2还是X3
X3和X1
宝马X3M和X4M
买X1还是买X3
2Xx2等于多少
相关问题
1/1x2x3+1/2x3x4+1/3x4x5+------...
1/1x2x3+1/2x3x4+1/3x4x5+.........
求和:1X2X3+2X3X4+3X4X5+...+98X99...
1/1x2x3+1/2x3x4+....+1/98x99x1...
1/1x2+1/2x3+1/3x4+......+1/98x...
3/1x2x3+5/2x3x4+7/3x4x5+....+1...
1/1x2+1/2x3+1/3x4+……+1/98x99+1...
1x2x3/2+2x3x4/2+3x4x5/2+.........