Posted by **Sabrina** on Thursday, January 20, 2011 at 11:03am.

a)cos4x-sin4xcot2x=-1

b)1+sinx+cosx/1+sinx-cosx=cot(x/2)

i tried to ask my teacher but she doesnt know please help me!

- math trig identities -
**Sabrina**, Thursday, January 20, 2011 at 12:13pm
Anyone help!!!!!

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