$3-7)e^{-5}.$

$e^{-x}=1-x+\frac{x^2}{2}-\frac{x^3}{3!}+$cdots

$e^{-x}=\frac{1}{e^x}=\frac{1}{1+x+\frac{x^2}{2}+\frac{x^3}{3!}+\text{c}\text{d}\text{o}\text{t}\text{s}}$

$6\mathrm{.}737947{10}^{-3},.$

$20,$

$.$