Mr. Unit Circle

The unit circle is very useful in many trigonometric equations. The unit circle is set on a graph with the main points being at 0, 90, 180, 270, and 360 degrees. In between these angles are several smaller angles such as 45 degrees and 60 degrees and all of these have a radian measure and points on them. The points on the angles correspond to their sine and cosine with sine equalling the y value and x equalling the cosine value. Tangent can also be represented in these points through sine/cosine or y/x. Here is a picture of a unit circle. 

Law of Sines/Cosines

The law of sines and cosines are two ways to solve triangles when they are not right triangles. The law of sines can be used when you have two sides and an opposite angle or two angles and an opposite side. The equation is sinA/a=sinB/b=sinC/c with the capital letters equaling the angles and the lowercase letters equaling the side lengths. The law of cosines can be used when you have 2 sides and an included angle or three sides and no angles. The equations for law of cosines are a^2=b^2+c^2-2(b)(c)(cosA), b^2=a^2+c^2-2(a)(c)(cosB), c^2=b^2+a^2-2(b)(a)(cosC).