Linear approximation

Linear Approximation is a method of approximating otherwise difficult to find values of a function by taking the value of a nearby tangent line instead of the function itself. This process is also called Tangent Line Approximation.

In some situations, it is easy to calculate the value f(a) of a function f, but difficult or impossible to calculate nearby values of f. In this case, mathematicians calculate the tangent line of f(a) at the point ( a, f(a) ) and use values calculated by this line instead of f itself.