Linear function (calculus)

This article is missing information about the case of multivariate functions and vector valued functions, which must be considered, as this article is linked to from Jacobian matrix. Please expand the article to include this information. Further details may exist on the talk page. (February 2020)

In calculus and related areas of mathematics, a linear function from the real numbers to the real numbers is a function whose graph (in Cartesian coordinates) is a non-vertical line in the plane.^[1] The characteristic property of linear functions is that when the input variable is changed, the change in the output is proportional to the change in the input.

Linear functions are related to linear equations.