Special Angles and Trigonometric Functions 1

Hey everyone!

Here’s the summary from our lesson in Special Angles and Trigonometric Functions 1.

We should keep in mind to use SOH-CAH-TOA in order to determine trigonometric functions of a Right Triangle and their reciprocals: csc for sin, sec for cos and cot for tan.

The special triangles below will help us find the trigonometric ratios of 30°, 45° and 60°:

         a)      45°-45°-90° Triangle                                                                 b) 30°-60°-90° Triangle

     

   

*Don`t forget to check for the signs ( ₊ or -)

   using the CAST rule. With this, we identified

that on Q2, all trig. functions are positive.

*As you can see, this problem consists of a quadrantal angle so it has a terminal side coinciding with a coordinate axis.Therefore, its trig function value is determined by the coordinates of the point where the terminal side intersects the circle.