(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

For which real numbers c is [tex](e^x+e^{-x})/2 \leq e^{cx^2}[/tex] for all real x?

2. Relevant equations

3. The attempt at a solution

I think you can expand both sides into series and term by term compare them. The left side is

[tex]\sum_{n=0}^{\infty}\frac{x^{2n}}{2n!}[/tex]

Can someone help me with the right side?

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# Homework Help: Taylor series

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