Why is it that e.g. 4ˆ-s = 1/4 s?

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Hi! I hope my question is understandable. This is something I never quite understood.

Why is it that when you put the negative unit in the exponent that it can be translated into a fraction?

(I hope this makes sense! English is not my first language!)

Thanks in advance for the answers!

In: Mathematics

3 Answers

Anonymous 0 Comments

Basically the same as the other answers but perhaps a slightly different persepctive. We essentially just define x^(-n) = 1/x^n so that the rules of exponentiation still hold. Namely we know that if n and m are positive integers

then x^(n+m)=x^(n)*x^(m) and so we just define negative exponentiation so this relation continues to hold ie. 1=x^(0)

=x^(n-n)=x^(n)*x^(-n) implies x^(-n)=1/x^n.

Anonymous 0 Comments

You keep dividing by that number and it eventually goes into fractions. A quick way to think about it is this :

4^4 = 4 x 4 x 4 x 4 = 256

4^3 = 4 x 4 x 4 = 64 and also = 256 ÷ 4

4^2 = 4 x 4 = 16 and also = 64 ÷ 4

4^1 = 4 = 4 and also = 16 ÷ 4

4^0 = 1 and also = 4 ÷ 4

4^(-1) = 1/4^1 = 1/4 and also = 1 ÷ 4

4^(-2) = 1/4^2 = 1/16 and also = (1/4) ÷ 4

Anonymous 0 Comments

If I’m not mistaken you’ve gotten the rule wrong.
4^-s = 1/4^s not 1/4s

So exponential are the base multiplied by itself so 4^3 = 4 *4 *4

If you then reduce the power by 1 you are basically dividing by the base.

4^2 = 4 *4 which is the same as (4^3 ) /4 which equals 4 *4 *4 /4

So 4^1 = 4 therefore 4^0 = (4)/4 =1

If you keep reducing the power you get 4^-1 = (4^0 )/4 which is 1/4

Then 4^-2 = (4^-1 )/4 which equals (1/4)/4 or 1/4^2

……4^-s = 1/4^s