Evaluate the following limit:
lim x -> 2 { [( 4 ) / ( x^2 - 4 )] - [ 1 / (x-2) ] }
(( plz help me to solve this question ,,,thz a lot ))
limits question....urgent
2007-09-15 5:12 am
回答 (2)
2007-09-15 5:17 am
✔ 最佳答案
lim x -> 2 [( 4 ) / ( x^2 - 4 ) - 1 / (x-2)]=lim x ->2 [(4)/(x+2)(x-2)-1/(x-2)]
=lim x ->2 [(4-x-2)/(x-2)(x+2)]
=lim x ->2 [-(x-2)/(x-2)(x+2)]
=lim x ->2 [-1/(x+2)]
=-1/(2+2)
= -1/4//
2007-09-15 5:21 am
lim x -> 2 { 4 / [(x+2)(x-2)] - [(x+2) / [(x+2)(x-2)] }
=lim x -> 2 [4-(x+2)] / [(x+2)(x-2)]
=lim x -> 2 (-x+2) / [(x+2)(x-2)]
=lim x -> 2 -(x-2) / [(x+2)(x-2)]
=lim x -> 2 - 1 / (x+2)
= - 1 / (2+2)
=-1/4
=lim x -> 2 [4-(x+2)] / [(x+2)(x-2)]
=lim x -> 2 (-x+2) / [(x+2)(x-2)]
=lim x -> 2 -(x-2) / [(x+2)(x-2)]
=lim x -> 2 - 1 / (x+2)
= - 1 / (2+2)
=-1/4
收錄日期: 2021-04-13 13:29:43
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20070914000051KK03558