integral transform

In mathematics, a function that results when a given function is multiplied by a so-called kernel function, and the product is integrated (see integration) between suitable limits.

Its value lies in its ability to simplify intractable differential equations (subject to particular boundary conditions) by transforming the derivatives and boundary conditions into terms of an algebraic equation that may easily be solved. The solution yielded must be converted to the final solution using an inverse transformation. Several integral transforms are named for the mathematicians who introduced them (Fourier transform, Laplace transform).

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▪ mathematics

      mathematical operator that produces a new function f(y) by integrating the product of an existing function F(x) and a so-called kernel function K(x, y) between suitable limits. The process, which is called transformation, is symbolized by the equation f(y) = ∫K(x, y)F(x)dx. Several transforms are commonly named for the mathematicians who introduced them: in the Laplace transform, the kernel is e^−xy and the limits of integration are zero and plus infinity; in the Fourier transform, the kernel is (2π)^−1/2e^−ixy and the limits are minus and plus infinity.

      Integral transforms are valuable for the simplification that they bring about, most often in dealing with differential equations (differential equation) subject to particular boundary conditions. Proper choice of the class of transformation usually makes it possible to convert not only the derivatives (derivative) in an intractable differential equation but also the boundary values into terms of an algebraic equation that can be easily solved. The solution obtained is, of course, the transform of the solution of the original differential equation, and it is necessary to invert this transform to complete the operation. For the common transformations, tables are available that list many functions and their transforms.

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