Last Updated on September 26, 2021

A Mild Intro to Taylor Series

Taylor series expansion is an amazing concept, not just the world of mathematics, however also in optimization theory, function approximation and machine learning. It is extensively used in numerical computations when quotes of a function’s worths at various points are required.

In this tutorial, you will find Taylor series and how to approximate the values of a function around various points utilizing its Taylor series expansion.

After completing this tutorial, you will know:

  • Taylor series growth of a function
  • How to approximate functions using Taylor series growth

Let’s start.

A Gentle Introduction To Taylor Series. Photo by Muhammad Khubaib Sarfraz, some rights reserved.

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“378”/ > A Mild Introduction To Taylor Series. Picture by Muhammad Khubaib Sarfraz, some rights scheduled. Tutorial Introduction This tutorial is divided into 3 parts; they are

  1. : Power series and Taylor series
  2. Taylor polynomials
  3. Function approximation using Taylor polynomials

What Is A Power Series?

The following is a power series about the center x=a and continuous coefficients c_0, c_1, and so on

What Is A Taylor Series?

It is a fantastic fact that functions which are considerably differentiable can generate a power series called the Taylor series. Expect we have a function f(x) and f(x) has derivatives of all orders on a provided period, then the Taylor series created by f(x) at x=a is given by:

The 2nd line of the above expression gives the worth of

the kth coefficient. If we set a=0, then we have an expansion called the Maclaurin series growth of f(x). Examples Of Taylor Series Growth

Taylor series produced by f(x) = 1/x can be discovered by first distinguishing the function and discovering a basic expression for the kth derivative.

The Taylor series about various points can now


discovered. For example: Taylor Polynomial A Taylor polynomial of

order k, generated by f(x)at x= a is offered by: For the example of f (x)=1/x, the Taylor polynomial

of order 2 is given by: Approximation by means of Taylor Polynomials We can approximate the value of a function at a point x=an using Taylor polynomials. The higher the order of the polynomial, the more the terms in the polynomial and the closer the approximation is to the real value of the function at that point. In the graph listed below, the function 1/x is plotted around the point x=1(left)and x=3(right). The line in green is the actual function f(x )=1/x. The pink line represents the approximation through an order 2 polynomial. The real function(

green)and its approximation(pink) More Examples of Taylor Series Let

‘s take a look at the function g(x) =e ^ x. Noting

the reality that the kth order derivative of g( x)is likewise g(x ), the growth of g(x) about x=a, is provided by:

For this reason, around x=0, the series growth of g(x) is provided by (acquired by setting a=0):

The polynomial of order k created for the function e ^ x around

the point x=0 is provided by: The plots listed below program polynomials of various orders that approximate the value of e ^ x around x=0. We can see that as we move away from absolutely no, we require more terms to approximate e ^ x more precisely. The green line representing the actual function is concealing behind the blue line of the approximating polynomial of order 7.

Polynomials of differing degrees that approximate e ^ x

Taylor Series In Machine Learning

A popular approach in machine learning for finding the optimum points of a function is the Newton’s technique. Newton’s technique utilizes the second order polynomials to approximate a function’s value at a point. Such approaches that utilize second order derivatives are called 2nd order optimization algorithms.


This section notes some ideas for extending the tutorial that you might wish to check out.

  • Newton’s method
  • 2nd order optimization algorithms

If you explore any of these extensions, I ‘d like to know. Post your findings in the comments below.

More Reading

This section provides more resources on the subject if you are seeking to go deeper.




  • Pattern acknowledgment and machine learning by Christopher M. Bishop.
  • Deep knowing by Ian Goodfellow, Joshua Begio, Aaron Courville.
  • Thomas Calculus, 14th edition, 2017. (based upon the original works of George B. Thomas, revised by Joel Hass, Christopher Heil, Maurice Dam)
  • Calculus, 3rd Edition, 2017. (Gilbert Strang)
  • Calculus, 8th edition, 2015. (James Stewart)


In this tutorial, you discovered what is Taylor series growth of a function about a point. Specifically, you learned:

  • Power series and Taylor series
  • Taylor polynomials
  • How to approximate functions around a value using Taylor polynomials

Do you have any questions?

Ask your questions in the remarks listed below and I will do my best to answer