YT Math: Seeing i to i

There are a lot of videos on this for some reason, even though an introduction to complex numbers is all you need to address it.

Begin by rewriting i in polar form: e^{\frac{\pi}{2} + 2k\pi},\ k \in \mathbb{Z}. You can arrive at this by plotting i on the complex plane or by noting i = \cos \frac{\pi}{2} + i \sin \frac{\pi}{2} and using Euler’s formula.

Now raise this quantity to the i^{\text{th}} power:

    \[e^{i^2(\frac{\pi}{2} + 2k\pi)}\]

    \[e^{\frac{-\pi}{2} - 2k\pi}\]

This is now clearly a real number like the titles say, as it’s e with a real exponent.

If we take k = 0, we’ll have e^\frac{-\pi}{2}, which we can expect as a sanity check to have a value on the interval (0, 1). A calculator confirms this is the 0.20787... number in that thumbnail. \blacksquare


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