Express Cos( 7pi/3) as a trigonometric function of an angle in Quadrant I.
Based on “angle in Quadrant 1” you will need to use the Unit Circle to determine your expression. From what I learned the trick about the Unit Circle is that the angle across each quadrant determines the next answer across. Diagonally from 4 pi/3 is 7 pi/3. Therefore your angle should be 60 degree. Cos 7pi/3 equals 1/2 or .5, which is in Quadrant 1