SearchOnMath

Factorials apply only to nonnegative integers but can be extended to complex numbers with positive real parts using the Gamma function, \(\Gamma(n) = \int_0^\infty e^{-x}x^{n-1}dx\).

The heat equation, \(\frac{\partial \varnothing}{\partial t} = D \nabla^2 \varnothing\), uses the Laplacian of \(\varnothing\) to express diffusion through a medium.

The total probability formula, \(P(A) = \sum_k P(A \cap B_k)\), relates the occurrence of an event \(A\) to that of several mutually exclusive events (\(B_k\)'s).