Get rid of obvious stuff first; you'll get
0 = 1 - sec²x + tan²x
Name:
Anonymous2008-12-02 17:23
OP: What? I need steps!
Name:
Anonymous2008-12-02 17:44
>>3
On the right side, sin^2(x)/cos^2(x) = tan^2(x), and tan^2(x) - sec^2(x) = -1, so you have 2 - sin(x). Replace 2 with 1 + sin^2(x) + cos^2(x) and you're done.
Name:
Anonymous2008-12-02 18:46
Protip: EVERY trig identity can be proved by writing everything in sines and cosines and using sin^2 x + cos^2 x = 1