## anonymous one year ago Which equation is not an identity? tan(–t) = –tan t tan t(csc t + cot t) = sec t + 1 sin tcot t = cos t cos2t − sin2t = –1

1. anonymous

@Shalante @oldrin.bataku

2. anonymous

i feel like it is d but in like 50% sure

3. anonymous

@UsukiDoll

4. UsukiDoll

thinking...

5. UsukiDoll

I've seen $\cos^2t-\sin^2t$ before. I think it was one of the identities for cos2t

6. anonymous

okay so d is right?

7. UsukiDoll

yeah... there's also another identity which is $\large \cos^2t+\sin^2t=1$ but rearranging them a bit gives me $\large \cos^2t=1-\sin^2t$ $\large \sin^2t=1-\cos^2t$

8. anonymous

d was right lol this stuff is so confusing

9. UsukiDoll

|dw:1438846787051:dw|

10. UsukiDoll

one big huge trig list........and parts of it exist beyond trig.

11. anonymous

okay i posted another question do you think you could help me on that one as well?