eli5: why is x⁰ = 1 instead of non-existent?

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It kinda doesn’t make sense.
x¹= x

x² = x*x

x³= x*x*x

etc…

and even with negative numbers you’re still multiplying the number by itself

like (x)-² = 1/x² = 1/(x*x)

In: 1797

38 Answers

Anonymous 0 Comments

The best explanation I’ve ever found for this, and for my students (I’m a math teacher), is that of a number line.

Ask yourself, if you were to draw 3^2 on a number line, you’d be drawing 2 leaps (because this is a power of 2), each representing a multiplication of 3 (because that’s the base of our power).

So the question is – where do these leaps begin? Well they have to start from 1 (because if you start at 0 and multiply, you’ll go nowhere). Any index (power) actually begins at 1, and is a series of multiplications from there.

Example: 4^5. Begin at 1, multiply by 4, 5 times.

So then the answer to your question becomes trivial. Any number, let’s call it x, to the power of 0.

Begin at 1, multiply by x, 0 times. Well because you’re doing it 0 times, you’re not moving from 1. You’re staying exactly there.

That’s why anything to the power 0 is 1. It’s where our indices begin, and we take 0 steps – we stay still!

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