What trigonometric identity is this? (1 - cos^2 x)

[MiccyNarc]

As the title says, is that a trig identity or am I missing something here? This keeps coming up and it's driving me insane. Thanks for any help!
EDIT: Nevermind, found it.

One more question, then that means sin^2 x + 1 - cos^2x = sin^2 x + sin^2 x = 2sin^2 x?
Or am I still missing something here. I hate this stuff

 

[Shamrock]

Sounds correct. Looks correct.
Should be correct.

If its not, then I shouldn't be taking a maths class.

 

[TheHamster22]

Looks right, but not terribly useful D: D:

 

[Shamrock]

Looks right, but not terribly useful D: D:

Agreed.

 

[MiccyNarc]

Looks right, but not terribly useful D: D:

Yeah but I need to pass this course and the homework is kicking my ass.

 

[Uriel]

sin^2 x + 1 - cos^2x = sin^2 x + sin^2 x = 2sin^2 x = Baykuns to the 4th power divided by 27.

I have no idea, you'd get further screaming at a can of peaches than asking me to help you.

 

[DEATHMASTER]

Look at your notes, if you took any it's all there, or look at your book.

 

[AntiAnto]

Considering the radius of this circle equals to one, then Pythagoras tells us that

In the circle, each side of a given triangle is given by either cos (x) or sin (x). So we can deduce this equation

 

[MiccyNarc]

Look at your notes, if you took any it's all there, or look at your book.

The expected smartass response.
No, my teacher did not go through every single possible trig identity, and I've been through all of it in my book, and it's much like finding a needle in a haystack.

 

[zleppelin]

it's the pythagorean theorem.cos(x)^2 + sin(x)^2 = 1

 

[Stigmata]

These identities are crazy useful as soon as you start going into higher-level algebra and calculus.

 

[AntiAnto]

Anyway, if that wasn't clear at all Miccy, I'm sure Wikipedia does it better than us.



http://en.wikipedia.org/wiki/Pythagorean_trigonometric_identity
http://en.wikipedia.org/wiki/Trigonometric_identity