救命啦,帮我算下.现在30分,19+19又1/2+7又1/4+3又1/8+8又1/16+4又1/32(1/2-1/4)+(1/4-1/6)+(1/6-1/8)+.+(1/48-1/50)1/1*2+1/2*3+1/3*4+.+1/98*99+1/99*1001+3又1/6+5又1/12+7又1/20+9又1/30+11又1/42+13又1/56+15又1/72+17又1/90
救命啦,帮我算下.现在30分,
19+19又1/2+7又1/4+3又1/8+8又1/16+4又1/32
(1/2-1/4)+(1/4-1/6)+(1/6-1/8)+.+(1/48-1/50)
1/1*2+1/2*3+1/3*4+.+1/98*99+1/99*100
1+3又1/6+5又1/12+7又1/20+9又1/30+11又1/42+13又1/56+15又1/72+17又1/90
19+19又1/2+7又1/4+3又1/8+8又1/16+4又1/32
=60又31/32
(1/2-1/4)+(1/4-1/6)+(1/6-1/8)+...........+(1/48-1/50)
=3/5
1/1*2+1/2*3+1/3*4+.......+1/98*99+1/99*100
=(2+100)*99/2=5049
1+3又1/6+5又1/12+7又1/20+9又1/30+11又1/42+13又1/56+15又1/72+17又1/90
=71又7/18
121
19+19又1/2+7又1/4+3又1/8+8又1/16+4又1/32
=19+19+1/2+7+1/4+3+1/8+8+1/16+4+1/32
=(19+19+7+3+8+4)+(1/2+1/4+1/8+1/16+1/32)
=60+(16/32+8/32+4/32+2/32+1/32)
=60+31/32
=60又31/32
其他几个我就做不出来了!!!
先说第三题。
原式=(1-1/2)+(1/2-1/3)+(1/3-1/4)+。。。。。。+(1/98-1/99)+(1/99-1/100)=1-1/100=99/100
1)整数部分叠加,分数部分叠加,得到原式=60+(1/2+1/4+1/8+1/16+1/32)
分数部分,1/2+1/4+1/8+1/16+2/32-1/32
=1/2+1/4+1/8+1/16+1/16-1/32
=1/2+1/4+1/8+1/8-1/32
.
=31/32
结果等于60又31/32
2) (1/2-1/4)+(1/4-1/6)+(1/6-1/8)+.+(1/48-1/50)
=1/2-1/4+1/4-1/6+1/6-1/8+.+1/48-1/50)
=1/2-1/50
=24/50
=12/25
3)1/1*2+1/2*3+1/3*4+.+1/98*99+1/99*100
=(1-1/2+1/2-1/3+.+1/99-1/100)
=1-1/100
=99/100
4)
1+3又1/6+5又1/12+7又1/20+9又1/30+11又1/42+13又1/56+15又1/72+17又1/90
=(3+5+7+9+11+13+15+17)+(1+1/2*3+1/3*4+.+1/9*10)
=(3+17)+(5+15)+(7+13)+(9+11)+(1+1/2-1/3+.+1/9-1/10)
=80+1+1/2-1/10
=81+2/5
=81又2/5
全部答完,yeah~