<p>How do you get the frequency and period? Say if you have 3 sin 2x, is the 2 the frequeny? How do you get the period from that? I know that the period/4 equals the unit. </p>
<p>I've seen questions where it adds sin, cos, and squares them sometimes, and this makes no sense to me! I've seen a couple of things in princeton review about sin/cos=tan and (sin+cos)^2=1, but if I don't know how to do other ones, should I just come up with my own angle(theta) and see if plugging in works?</p>
<p>If by frequency you mean amplitude then you take the number on the outside (in this example 3) put it under absolute value and you get your amplitude. </p>
<p>For Period of sin and cos you take the number closest to the x and divide 2pi by that number. So in this example you have to take 2pi/2= pi. so pi is your period</p>
<p>its similar for tangent except you use pi rather than 2pi.</p>
<p>(sin+cos)^2 is not 1. (sin^2 + cos^2) =1</p>
<p>Personally I would not worry too much on trig identities as there are at most 3 questions on them (Usually 1 or 2) and the almost always give you a formula you could use to solve them. But if you want to save your self time go ahead and google Trig Identities and learn.</p>