1 answer
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cot(-θ)(secθ)
= cos(-Ø)/sin(-Ø)(1/cosØ
= (cosØ/-sinØ)(1/cosØ
= - 1/sinØ
= - csc(Ø)
(test your answers with some weird angle, don't use 30's , 60's, or 45's)
2. you will have to know that
cos(90°-x) = sinx
take it from there
3. 3sin2xcos2x - sin4x
= 3sin2xcos2x - 2sin2xcos2x
= sin2xcos2x
or (1/2)sin4x
4. change everything to sines and cosines and just mess around with it.
make sure to test your answer vs the original with some strange angle on your calculator.