singaporeolevelmaths

Simple Tips for Better Maths Results!

completing square

E-Maths: Completing Square Step-by-Step Video (Part 1)

I was talking to my Secondary 3 students in my O-Level E Maths weekly tuition class on Quadratic when they expressed disgust for the technique of Completing Square.

A similar thing happened when Completing Square was an alternative method offered to Equation of Circle concept. There was a collective yucks from the class.

I hope my video will ease the yuckness many students find with completing square technique and give you some hope to conquer it!

Test out your understanding by leaving your answer for the bonus question in the comments below!

Direct link to video: http://www.youtube.com/watch?v=bf8PfyP2h74

A-Math: General Equation of Circle - Linked to Completing Square

In the previous post, I have discussed the standard equation of circle which is derived from distance formula.

The other equation of circle is known as General.

Example

general-eqn-circle-example

To answer this question easily, you need your completing square technique (Read about the steps here) which many students dislike!

You notice in the step by step solution, the general equation is converted into a standard equation through the following steps:

  1. Arrange all x terms and y terms together
  2. Start completing square
  3. Simplify all constants
  4. Set equation into standard equation of circle

General Equation to Standard Equation of Circle

convert-general-standard

Radius = 5 and Centre of circe = (4, 1)

I hope you have a better understanding on equation of circle.