Well, I never had Chaos Theory in any of my courses either... The millennium problems are so advanced that they probably won't mention them except maybe in PhD in Math.
As for Euler's identity, I never heard of it before this but it made sense. We're familiar with all its components.
Yep, that we are about the Euler's identity.
What is it used to solve? Or identify.
The thing is, all of these are known numbers:
So using the equation you can find one of them if you have the others, but it doesn't make sense to find them through this equation instead of simpler equations.
I'm not sure... Just asked ChatGPT and it gave me a long list of fields it affects inlcuding Physics, Engineering and Quantum Mechanics... It doesn't tell how it's used though.