Help with learning a few things in trig

Question

kingdex04 · Answer

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kingdex04 · Answer

i have no idea on how to work these just yet....anyone wanna help me out here

mathmale · Answer

I'd suggest you look through these problems and pick whichever among them are within your ability to do now.  Then we could move on to harder problems.  Have you any book or online notes for this course?  If so, have you looked through them for principles that apply to these questions?

I'd suggest you actually evaluate as many of the expressions as you can, both those identified with letters and those identified with numbers.  Matching answers should become easier if you'd do this first.

As an example:  Note that cos 35 = cos (-35).  Why?  Because the cosine function is even, producing the same result for an angle of -35 as for an angle of +35.  Note that the sine function is odd.  Which other principles applying to these trig expressions can you recognize?  For example:  cos (a + b) is the sum formula for the cosine function:

cos (a+b) = cos a cos b - sin a sin b.  (You have to know this formula and others like it.  What is sin (a+b)? )