Trig Identities from Reflections and Rotations
This video introduces the idea of solving practice problems involving reflections and rotations of the trigonometric functions.
To solve these problems on the unit circle, notice that the x coordinate is equal to the cosine of the angle theta and the y coordinate is equal to the sine of theta. After reflecting or rotating the angle, compare the x and y coordinates of the new point with the original one.
Khan Academy exercise to practice:
1. Trig Identities from Reflection and Rotation: https://www.khanacademy.org/math/trig...
EulersAcademy.org