SearchOnMath

The wave equation, \(\frac{\partial^2u}{\partial t^2}= c^2\nabla^2 u\), relates how \(u\) varies with time and with the spatial coordinates as a wave propagates with speed \(c\).

Shannon's entropy, \(H(X) = -\sum_{x \in \mathbf{X}} p(x) \log p(x)\), measures how informative the mass function \(p\) is about the occurrence of the possible values of variable \(X\).

Newton's mutual attraction force for masses \(m_1\), \(m_2\) is \(F=G\frac{m_1 m_2}{d^2}\), where \(d\) is the distance between them and \(G\) is the gravitational constant.