有几道分数奥数题1. 1/2+(1/3+2/3)+(1/4+2/4+3/4)+.+(1/60+2/60+3/60+.+58/60+59/60)2. (1+1/2)×(1+1/4)×(1+1/6)×(1+1/8)×(1+1/10)×(1-1/3)×(1-1/5)×(1-1/7)×(1-1/9)4. 2/3+2/9+2/27+2/81+2/2435. 1又1/3
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有几道分数奥数题1. 1/2+(1/3+2/3)+(1/4+2/4+3/4)+.+(1/60+2/60+3/60+.+58/60+59/60)2. (1+1/2)×(1+1/4)×(1+1/6)×(1+1/8)×(1+1/10)×(1-1/3)×(1-1/5)×(1-1/7)×(1-1/9)4. 2/3+2/9+2/27+2/81+2/2435. 1又1/3
有几道分数奥数题
1. 1/2+(1/3+2/3)+(1/4+2/4+3/4)+.+(1/60+2/60+3/60+.+58/60+59/60)
2. (1+1/2)×(1+1/4)×(1+1/6)×(1+1/8)×(1+1/10)×(1-1/3)×(1-1/5)×(1-1/7)×(1-1/9)
4. 2/3+2/9+2/27+2/81+2/243
5. 1又1/3+3又1/15+5又1/35+7又1/63+9又1/99+11又1/143
6. 4×4/4²-1 + 6×6/6²-1 + 8×8/8²-1 + 10×10/10²-1 + 12×12/12²-1
有几道分数奥数题1. 1/2+(1/3+2/3)+(1/4+2/4+3/4)+.+(1/60+2/60+3/60+.+58/60+59/60)2. (1+1/2)×(1+1/4)×(1+1/6)×(1+1/8)×(1+1/10)×(1-1/3)×(1-1/5)×(1-1/7)×(1-1/9)4. 2/3+2/9+2/27+2/81+2/2435. 1又1/3
1答案:原式=0.5+1+1.5+2+2.5……+30
=(0.5+30)×30÷2
=457.5
2、3/2x5/4x7/6x9/8x11/10x2/3x4/5x6/7x8/9约分后等于11/10
3、分子=1975x(1+10001+100010001)分母=1998x(1+10001+100010001)
约分后1975/1998
4、2/3+2/9+2/27+2/81+2/243从最后加起:2/243+2/81+2/27+2/9+ 2/3=按等比数列来算:
和=(末项×公比—首项)除以(公比—1)=(2/3x3—2/243)÷(3—1)=
(2—2/243)÷2=1-1/243=242/243
5.原式=(1+3+5+7+9+11)+(1/3+1/15+1/35+1/63+1/99+1/143)
=36+(1/1x3+1/3x5+1/5x7+1/7x9+1/9x11+1/11x13)
=36+1/2x(1-1/3+1/3-1/5+1/5-1/7+1/7-1/9+1/9-1/11+1/11-1/13)
=36+1/2x(1-1/13)
= 36+1/2x12/13=36又6/13
6.第六题就是:1又1/15+1又1/35+1又1/63+1又1/99+1又1/143
=5+1/2x(1/3-1/5+1/5-1/7+1/7-1/9+1/9-1/11+1/11-1/13)
=5+1/2x(1/3-1/13)
=5又5/39