sin t = tan t cos t
is that an identity??


(cot^2)x =(csc x - 1)(cscx + 1)
is that an identity??

ten q


i need it in 10 minutes

oh f**k, i know this. lemme refresh my memory.

I don't think any of those are Identities.

http://www.math2.org/math/trig/identities.htm

^ you can simplify though.

tanx = cosx/sinx so tanxcosx = cos2x/sinx

so bring the sinx with the other sinx

sinx sinx = cos2x
sin2x =cos2x

is that right so far?

Tan X = Sin X/ Cos X , Not Cos x / Sin x.

Right?

I forgot. If tanx=sinx/cosx then...

sinx=(sinx/cosx)cosx
sinx=sinx
1=1?

No, I think tanx=cosx/sinx

//edit, my bad. you're right.

if it's 1=1 then it is an identity.




as for the next one: (cot^2)x =(csc x - 1)(cscx + 1)

cot2x = csc2x - 1

i'm stuck

Yeah, that's right. I forgot about simplifying. >.<;;

Problem: (cot^2)x =(csc x - 1)(cscx + 1)

Identity: cot^2(x)= csc^2(x) - 1
Distribute.
= csc^2 +csc x-csc x - 1
= csc^2 - 1
cot^2=cot^2

It's an Identity.

yay, we did it! lol

ahaha. Under 10 minutes...I think.

thanks!!!!!!!!!!!!!!!!!!