Linear Approximation*

Linear approximation is an approximation of a general function using a linear function.

They are widely used in the method of finite differences to produce first order methods for solving or approximating solutions to equations.

In essence, linear approximation is using an equation of a tangent line based on a point close to a value to approximate that value of a function rather than plugging it directly into the function.

It tends to be easier to plug the input into an equation of a tangent line rather than the function itself.