## Friday, 10 April 2009

### Constants and Variables

In maths, you will encounter many "letters". This "letters" are the symbols used to form equations and mathematical expressions.

("letters" here may mean symbols like the theta, beta, etc)

Some of these symbols are constants and some represent variables.

Knowing what are constants and variables is crucial for mastery of maths learning.

What are constants?
Constants, as the word literally means, are items that have number that never change.

What are variables?
Variables are symbols that changes in value.

Example A:
y = 3 x + 2

y and x are variables, and 3 and 2 are obviously constants.

Example B:
log x = 5y

x and y are variables , and 5 is constant.

Example C:
y = mx + c ( for straight line equation)

y and x are variables, and m and c are constants.

This may be confusing to some maths students when they start plotting graphs.
Here, the straight line is continuously moving with the value of x and y.

So why is the "m" identified as constant?

You need to know that "m" represents the "GRADIENT" of the line.
The line has the same slope at any value of x and y.
Thus "m" is a constant.
This is a typical concept that commonly goes wrong.

Therefore when you really understand what changes are considered "variables" and those that remain stable are known as "constants", you are in line for good maths study!

.

#### 1 comment:

differential equation of first order said...

Here is a simple definition of variable as a symbol for a number which is usually a letter like x or y called as Variable and a number on its own is called a Constant.When these two or more variables are joined together with the help of the symbols are called expressions.