In maths, there are various ways of writing the same thing. For example, we could say 5 equals 4 + 1, or 3 +2 or even 10 - 5.
5 = 4 + 15 = 3 + 25 = 10 -5
Essentially, we have just written the number 5 in a different way.
When we multiply a number with itself, lets say we represent that number using the letter a, we can write this as a x a.
Lets say a = 5,
so 5 x 5 = 25.
Another way of writing 5 x 5 is by using index form. We can rewrite 5 x 5 as 52.
If it were 5 x 5 x 5 x 5, we can write this as 54.
Imagine in an exam, during school or anywhere else writing5 x 5 x 5 x 5 x 5 x 5 x 5 x 5 x 5.
This would take a large amount of your time and you can easily make a mistake. For example, you might write an extra 5 by mistake. So by writing in index form, it is much easier just to write 59.
5 x 5 x 5 x 5 x 5 x 5 x 5 x 5 x 5 = 59
So any number can be written in index form.
If we wanted to write 1/2 x 1/2 x 1/2 in index form, it would be(1/2)2.
What if the power was negative?
What if the question was to find what 5-1 equals. When we have a negative power, we write 5-1 as 1/(51).
5-1 = 1/(51)
Lets say we have a-n, then we would write this as 1/(an). Some examples are below.
e.g. 64-4 = 1/( 644) a = 67, n = 4 2-10 = 1/( 210) a = 2, n = 10 10-3 = 1/(103) a = 10, n = 3
SO NOW WE KNOW HOW TO WRITE IN INDEX FORM AND WHAT IT MEANS.