how can i solve sigmoid function?

Question

$$\frac{1}{ 1-e^ {-(-3.0)}} = -0.052$$

$-0.052$ is the answer. This equation is sigmoid function. How could I get the answer like that? Please understand me T.T

Answer 1

In case you don't know, $e$ is a mathematical constant, and its approximate value is $e\approx2.718$. Applying it, we have:

$$\frac{1}{1-e^{-(-3.0)}}=\frac{1}{1-e^3}=\frac{1}{1-\left(2.718\right)^{3}}=-0.0524128512.$$