Legendre's differential equation

Etymology
Named after French mathematician Adrien-Marie Legendre (1752–1833).

Proper noun

 * 1)  The equation that defines the Legendre polynomials: $${d \over dx} \left[ (1-x^2) {d \over dx} P_n(x) \right] + n(n+1)P_n(x) = 0.$$