Chapter 3
Orthogonal Polynomials

The subject of orthogonal polynomials has important applications in physics, quantum mechanics, mathematical statistics, and other areas in mathematics.
Orthogonal systems of polynomials play an important role in analysis mainly because functions belonging to general classes can be expanded in series or orthogonal polynomials, such as Fourier series where the orthogonal system or polynomials is \[\{\cos nx\}^{\infty }_{n=1}.\] Emphasis will be placed on Legendre, Chebyshev, Jacobi, Laguerre and Hermite polynomials. We shall also present some applications.