1.(1+1/3)x(1—1/3)x(1+1/4)x(1—1/4)…(1+1/100)x(1—1/100) 2.1999+2000x1998/1999x2000-1 3.2002x1999-1957/42+1999x20014.1/2x4+1/4x6+1/8x10+1/10x12“/”是分数线
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1.(1+1/3)x(1—1/3)x(1+1/4)x(1—1/4)…(1+1/100)x(1—1/100) 2.1999+2000x1998/1999x2000-1 3.2002x1999-1957/42+1999x20014.1/2x4+1/4x6+1/8x10+1/10x12“/”是分数线
1.(1+1/3)x(1—1/3)x(1+1/4)x(1—1/4)…(1+1/100)x(1—1/100) 2.1999+2000x1998/1999x2000-1
3.2002x1999-1957/42+1999x2001
4.1/2x4+1/4x6+1/8x10+1/10x12
“/”是分数线
1.(1+1/3)x(1—1/3)x(1+1/4)x(1—1/4)…(1+1/100)x(1—1/100) 2.1999+2000x1998/1999x2000-1 3.2002x1999-1957/42+1999x20014.1/2x4+1/4x6+1/8x10+1/10x12“/”是分数线
1.=4/3x2/3x5/4x3/4x……x101/100x99/100
=(4/3x5/4x6/5x……x100/99x101/100)x(2/3x3/4x4/5x……x98/99x99/100)
=101/3x2/100
=101/150
2.请问是否忘了加括号?(1999+2000x1998)/(1999x2000-1)
=[(2000-1)+2000x(2000-2)]/[2000x(2000-1)-1]
=(2000x2000+2000-2000x2-1)/(2000x2000-2000-1)
=(2000x2000-2000-1)/(2000x2000-2000-1)
=1
3.(2002x1999-1957)/(42+1999x2001)
=(2002x1999-1999+42)/(2001x1999+42)
=[(2002-1)x1999+42]/(2001x1999+42)
=1
4.1/(2x4)+1/(4x6)+1/(6x8)1+/(8x10)+1/(10x12)
=1/4x(1/2+1/6+1/12+1/20+1/30)
=1/4x(1x1/2+1/2x1/3+1/3x1/4+1/4x1/5+1/5x1/6)
=1/4x(1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6)
=1/4x(1-1/6)
=5/24
(2),(3)题 没带括号,我看不太懂 (4)参考我 回答的这道题http://zhidao.baidu.com/question/449298640.html?oldq=1
第四题:估计题目抄错了!
1/2x4+1/4x6+1/6×8+1/8x10+1/10x12
=1/2(1/2-1/4)+1/2(1/4-1/6)+1/2(1/6-1/8)+1/2(1/8-1/10)+1/2(1/10-1/12)
=1/2(1/2-1/4+1/4-1/6+1/6-1/8+1/8-1/10+1/10-1/12)
=1/2 × (1/2 - 1/12)
余下略
1、原式=4/3*2/3*5/4*3/4*...*101/100*99/100=2/3*101/100=101/150
3.[1999x(2001+2002)x42-1957]/42