Comment on TIL science has its own swifties
HowAbt2day@futurology.today 3 weeks agoTwo questions for you my brother in god;
- what were the connections that were made in maths class that got the prof so excited?
- how long did you wait before removing the ever expanding schlong for your ever expanding sfinxter?
tetris11@lemmy.ml 2 weeks ago
For (1), we start with 2 definitions of cos(x) and sin(x), using their Taylor expansions
cos(x) = 1 - x^2^/2! + x^4^/4! - …
sin(x) = x - x^3^/3! + x^5^/5! - …
We now start with the definition of e^x^ Taylor expansion, and proceed to do some substitutions:
e^x^ = 1 + x + x^2^/2! + x^3^/3! + … + x^n^/n!
We can then substitute in: x=iθ (remembering that i^2^ = -1) to get
e^iθ^ = 1 + iθ - θ^2^/2! - iθ^3^/3! + θ^4^/4! + iθ^5^/5! + … etc…
If we group by real and complex, we can arrange the above as:
e^iθ^ = (1 - θ^2^/2! + θ^4^/4! + … ) + i(θ - θ^3^/3! + θ^5^/5! + … )
You should now realise that the left part resembles the expansion of cos(θ), and the right part resembles sin(θ). That is:
e^iθ^ = cos(θ) + i sin(θ)
Finally, we substitute in θ = π
e^iπ^ = cos(π) + i sin(π)
And we know that cos(π) = -1, and that sin(π) = 0, meaning that we end up with
e^iπ^ = -1 + i 0
or
e^iπ^ + 1 = 0
The teacher got excited because it is literally one of the most beautiful mathematical statements you can get, that connects five universal identities under a single statement: 0, 1, e, i, and π – and does so using 3 different operators (times, power, plus).
For (2), I’m still waiting as I think it’s currently holding the world together by sheer mass alone
HowAbt2day@futurology.today 2 weeks ago
Thank you for your service for both 1) and 2)!