48.2x0.059+0.41x4.8x怎么算
（1）26.4x25-2.6x250（2）48.2x0.059+0.41x4.82(3)1/2+1/6+1/12+1/20+......+1/9900(4)5/6-7/1...
（1）26.4x25-2.6x250 （2） 48.2x0.059+0.41x4.82 (3)1/2+1/6+1/12+1/20+......+1/9900
(4) 5/6-7/12+9/20-11/30+13/42-15/56+17/72 在线等 展开
(4) 5/6-7/12+9/20-11/30+13/42-15/56+17/72 在线等 展开
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26.4x25-2.6x250＝26.4x25-26x25＝（26.4－26）x25＝10
48.2x0.059+0.41x4.82＝4.82x0.59+0.41x4.82＝（0.59+0.41）x4.82＝4.82
1/2+1/6+1/12+1/20+......+1/9900＝1/2+（1/2-1/3）+(1/3-1/4)+(1/4-1/5)+......+(1/99-1/100)
=1/2+1/2-1/3+1/3-1/4+1/4-1/5+......+1/99-1/100=1/2+1/2+(1/3-1/3)+(1/4-1/4)+(1/5-1/5)+......+(1/99-1/99)-1/100=1-1/100=99/100
5/6-7/12+9/20-11/30+13/42-15/56+17/72
=(1/2+1/3)-(1/3+1/4)-(1/4+1/5)-(1/5+1/6)-(1/6+1/7)-(1/7+1/8)-(1/8+1/9)
=1/2+1/3-1/3+1/4-1/4+1/5-1/5+1/6-1/6+1/7-1/7+1/8-1/8+1/9
=1/2+(1/3-1/3)+(1/4-1/4)+(1/5-1/5)+(1/6-1/6)+(1/7-1/7)+(1/8-1/8)+1/9
=1/2+1/9=11/18
48.2x0.059+0.41x4.82＝4.82x0.59+0.41x4.82＝（0.59+0.41）x4.82＝4.82
1/2+1/6+1/12+1/20+......+1/9900＝1/2+（1/2-1/3）+(1/3-1/4)+(1/4-1/5)+......+(1/99-1/100)
=1/2+1/2-1/3+1/3-1/4+1/4-1/5+......+1/99-1/100=1/2+1/2+(1/3-1/3)+(1/4-1/4)+(1/5-1/5)+......+(1/99-1/99)-1/100=1-1/100=99/100
5/6-7/12+9/20-11/30+13/42-15/56+17/72
=(1/2+1/3)-(1/3+1/4)-(1/4+1/5)-(1/5+1/6)-(1/6+1/7)-(1/7+1/8)-(1/8+1/9)
=1/2+1/3-1/3+1/4-1/4+1/5-1/5+1/6-1/6+1/7-1/7+1/8-1/8+1/9
=1/2+(1/3-1/3)+(1/4-1/4)+(1/5-1/5)+(1/6-1/6)+(1/7-1/7)+(1/8-1/8)+1/9
=1/2+1/9=11/18
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