作业帮急 (12 21:16:10)1/(4－X) ＋ 1/(X－2)(X－3) + 1/(X－3)(X－4) 提示：1/N(N+1)=1/N－1/(N+1)
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急 (12 21:16:10)1/(4－X) ＋ 1/(X－2)(X－3) + 1/(X－3)(X－4) 提示：1/N(N+1)=1/N－1/(N+1)
急 (12 21:16:10)
1/(4－X) ＋ 1/(X－2)(X－3) + 1/(X－3)(X－4) 提示：1/N(N+1)=1/N－1/(N+1)
急 (12 21:16:10)1/(4－X) ＋ 1/(X－2)(X－3) + 1/(X－3)(X－4) 提示：1/N(N+1)=1/N－1/(N+1)
1/（4-X）+1/(X－2)-1/(X－3) +1/(X－3)-1/(X－4)
=2/(4－X) +1/(X－2)
=（2X-4+4-X）/(X－2)(4-X)
=X/(X－2)(4-X)
-1/(X-2)
原式=1/(4-x)+1/(x-3)-1/(x-2)+1/(x-4)-1/(x-3)=1/(2-x)
不是有提示么
解
原式=1/(4-x)+1/(x-3)-1/(x-2)+1/(x-4)-1/(x-3)
=-1/(x-4)+1/(x-3)-1/(x-2)+1/(x-4)-1/(x-3)
=-1/(x-2)
=1/(2-x)
1/(x-2)
原式=1/(4-X)+1/(X-2)-1/(X-3)+1/（X-3）-1/(x-4)=1/(X-2)
原式 = -1/(x-4) + 1/(x-3) - 1/(x-2) + 1/(x-4) - 1/(x-3)
= -1/(x-2)
= 1/(2-x)
(这是最简单的Partial Fraction一类的问题，通常有三种解决方法:Substitution, Comparision of Coefficient and Covering Up。本题...
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原式 = -1/(x-4) + 1/(x-3) - 1/(x-2) + 1/(x-4) - 1/(x-3)
= -1/(x-2)
= 1/(2-x)
(这是最简单的Partial Fraction一类的问题，通常有三种解决方法:Substitution, Comparision of Coefficient and Covering Up。本题极为简单，一眼就能看出Simple Fraction的形式。主要用在积分的简化。)
收起
=1/(4－X)+1/(X－3)-1/(X－2)+ 1/(X－4)-1/(X－3)
=-1/(X-4)+1/(X－4)+1/(X－3)-1/(X－3)-1/(X－2)
前四项两两抵消掉,剩下
=-1/(X－2)