In fact if you take a unit circle. So 2 = 3605 (so if = 1, arc length = 1) To go from rad deg , divide by 2 and multiple by 360. To go from deg rad, divide by 360 and multiple by 2. How to define them? sin = cos = sec = tan = cot = If is not acute, we look at the standard position of : Them to define trig functions: sin = cos = tan = These formulae extend the idea of using soh. Cah toa and right triangles to any situation i. e. any angles. Given by , determine r, x and y, and use these formulae. But if you prefer to pick a right triangle and either use the periodicity of trig functions or the rule to get the correct sign, then that is ok!!! Examples special triangles sin = cos = tan =
