Question 203109
Ok, first off let's bring up the unit circle


<img src="http://www.math.ucsd.edu/~jarmel/math4c/Unit_Circle_Angles.png">



This is a very handy tool. For each given angle (located on the spokes of the wheel), there is a point that lies on the circle. It turns out that the x coordinate of the point refers to the cosine of that given angle. Likewise, the y coordinate of the point refers to the sine of that angle. 


For example, the cosine of {{{pi/3}}} is {{{cos(pi/3)=1/2}}} since the x coordinate of this point is {{{x=1/2}}}. Also, the sine of {{{pi/3}}} is {{{sin(pi/3)=sqrt(2)/2}}} since the y coordinate of this point is {{{y=sqrt(2)/2}}}. You can use the unit circle to evaluate the sine/cosine of any given angle shown.



Finally, remember that we have the following identities:


{{{tan(x)=sin(x)/cos(x)}}}


{{{sec(x)=1/cos(x)}}}


{{{cot(x)=1/tan(x)=cos(x)/sin(x)}}}




I hope this will refresh something or help you get started. If this didn't help, please let me know or repost.