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/sci/ - Science & Math

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2485318 No.2485318 [Reply] [Original]

Wolfram Alpha claims that lim cos(x)/(e^x) as x->infinity is equal to 1. I find this weird since cos(x) would fluctuate between 0 and 1, but 1/e^x goes to 0. Thus I expected the answer to be 0 as a multiplication between a bounded function and a function tending to 0.

Can you guys help me figure this out?

>> No.2485350

U prolly put it in wrong. The fact is, as x--> 0, the answer is 1, but as x--> infinity the answer is 0

>> No.2485356
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2485356

using the actual Mathematica syntax on Wolfram Alpha

Limit[Cos[x]/Exp[x],x->Infinity]

gives the result 0. I don't know what you did there.

>> No.2485364

>>2485356
Neither do I. Tried again and now it's ok.
Thanks.

>> No.2485459
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2485459

>>2485318
you don't necessarily need the complicated syntax btw...
http://www.wolframalpha.com/input/?i=limit+of+cos%28x%29%2Fe^x+for+x+going+to+infinity