I find it interesting that some functions have specific values of a where f(a)=a.(adsbygoogle = window.adsbygoogle || []).push({});

Is there a way to find x that satisfies these following equations?:

e^-x=x or -log(x)=x

cos(x)=x

They seem like they should be interesting values, and I was trying to figure out if they could be represented using pi, e, or what not. Also, sin(x)=x has only the trivial value of 0 while tan(x)=x has infinitley many solutions.

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# Function f(a)=a

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