Proving the Pythagorean Theorem: The Relationship Between Sine and Cosine

[Mattara]

What is the English word for this rule? It doesn't sound right if I do a direct translation and google didn't turn up much.

Thank you

 

[neutrino]

(One of) The most famous trigonometric identity? ;) You'll generally find it in a list titled that way.

 

[Doc Al]

I think it's called the Pythagorean identity.

 

[neutrino]

Doc's right - http://en.wikipedia.org/wiki/Pythagorean_identity

 

[Mattara]

Thanks a lot, both of you. The name for it in my native language has been highly influenced by the number "1" :/

 

[Triss]

What would it be called in your native language? In Danish it is readily called "Idiotformelen" -- the idiot formula...

 

[Mattara]

That was funny. It would be "trigonometriska ettan" or "(the) trigonometry 1"