I have been studying for the GRE and taking note of various approximations to use on the exam, but I am having a difficult time finding a way to evaluate the following without the aid of a calculator(adsbygoogle = window.adsbygoogle || []).push({});

[itex]e^{-x}[/itex].

The GRE practice book has a problem to which the answer is

[itex]e^{-10} = 4.5 \times 10^{-5} [/itex].

I thought of using a Taylor series, but that is unwieldy... as were some other methods that I thought of.

I apologize if this is something I should know already... being that I have a B.S. in physics, but I'm really stuck here and I don't want to miss a problem like this just because I don't have a calculator.

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# Approximation for the Exponential

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