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the square root of an imaginary number

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Transcription

We know that taking the square root of a negative number gives you an imaginary number. But what happens if you take the square root of an imaginary number? You might think it's some unsolvable paradox, but watch what happens.

What actually is an imaginary number? It's a physical instruction. You have the number one and multiply by I, it rotates exactly 90° counterclockwise. And we can prove this with Euler's formula. I is equal to E to the power of I * pi over 2.

So, what happens when you take the square root? A square root just cuts the exponent in half. So, the formula becomes E to the I pi over 4. But what does that mean? Pi over 4 is 45° angle. So, the square root of I is just asking, "What is half of a 90° rotation?"

To find the exact coordinates, we'll just draw a right triangle and use basic trigonometry. The horizontal distance is cosine. The vertical distance is sine. At 45°, they're both exactly the square root of 2 over 2.

So, the square root of I isn't a paradox at all. It's a perfect physical coordinate. Square root of 2 over 2 + I * square root of 2 over 2. Imaginary numbers are just geometry.