lim極限數1題........

2007-09-12 4:44 am
lim (x→∞) [(x-2)/(x+1)]^x

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更新1:

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回答 (2)

2007-09-12 4:59 am
參考: My maths knowledge
2007-09-12 4:52 am
lim (x→∞) [(x-2)/(x+1)]^x
= lim (x→∞) [(1-2/x)/(1+1/x)]^x

Since 1-2/x < 1+1/x for all x > 0
Therefore, [(1-2/x)/(1+1/x)] < 1

For all y < 1
y^x approaches 0 for x tends to infinity

Therefore,
lim (x→∞) [(1-2/x)/(1+1/x)]^x
= 0


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