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lim x-->infinity (e^-x+2cos3x)

 Sep 5, 2014

Best Answer 

 #1
avatar+33653 
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It doesn't exist.

$$\lim_{x\rightarrow \infty}(e^{-x}+2\cos{3x})=\lim_{x\rightarrow \infty}(e^{-x})+\lim_{x\rightarrow \infty}(2\cos{3x})=0+\lim_{x\rightarrow \infty}(2\cos{3x})$$

The limit of cos(3x) as x goes to infinity is undefined as cos(3x) continues to oscillate between maximum and minimum values of 1 and -1 forever.

 Sep 6, 2014
 #1
avatar+33653 
+5
Best Answer

It doesn't exist.

$$\lim_{x\rightarrow \infty}(e^{-x}+2\cos{3x})=\lim_{x\rightarrow \infty}(e^{-x})+\lim_{x\rightarrow \infty}(2\cos{3x})=0+\lim_{x\rightarrow \infty}(2\cos{3x})$$

The limit of cos(3x) as x goes to infinity is undefined as cos(3x) continues to oscillate between maximum and minimum values of 1 and -1 forever.

Alan Sep 6, 2014

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