In terms of the unit circle diagram, Just as the sine and cosine can be found as ratios of sides of right triangles, so can the tangent We'll use three relations we already You don't have to remember all this information if you can just remember the ratios of the sides of a 45°45°90° triangle and a 30°60°90° triangleUnit Circle What you just played with is the Unit Circle It is a circle with a radius of 1 with its center at 0 Because the radius is 1, we can directly measure sine, cosine and tangent Here we see the sine function being made by the unit circle Note you can see the nice graphs made by sine, cosine and tangent Degrees and Radians The triangle is a special right triangle, and knowing it can save you a lot of time on standardized tests like the SAT and ACT Because its angles and side ratios are consistent, test makers love to incorporate this triangle into problems, especially on the nocalculator portion of
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