Introduction to Trigonometric Functions Honors Precalculus April 9-10, 2018 Mr. Agnew

Essential Question Essential Vocabulary What is the Unit Circle and how do we use it to evaluate trigonometric functions? Essential Vocabulary Unit Circle Degrees Radians Trigonometric Functions

The Unit Circle The Unit Circle is a circle centered at the origin with radius of 1. All of trigonometry is based on the unit circle. Trigonometry is the study of angles and the corresponding points on the unit circle.

Angles Angle in standard position One side on positive x axis and vertex at origin Angles can be positive or negative, and can be larger than 180°. Angles can be measured in degrees or in radians.

Converting Angles Angles can be measured in degrees or radians. Activity on radian measure To convert an angle… From Degrees to Radians: From Radians to Degrees:

Reference Angles All angles have a reference angle in the first quadrant. Coterminal angles… all angles have a coterminal angle between 0° and 360° OR 0 and 2π Examples…

The Unit Circle We are going to fill in the values on the unit circle “Special Angles” on the unit circle 30, 60, 90 and 45, 45, 90 “Special Angles” on unit circle give “special points” on the unit circle.

Evaluating Trig Functions Given a point (x,y) on the unit circle, the value of the 6 trig functions are…

Evaluating Trig Functions When evaluating a trig function… Find coterminal angle on unit circle Determine sign of value (All Students Take Calculus) Find reference angle Find value Examples, on & off calc

Evaluating Trig Worksheet Homework: 4/10/18 Evaluating Trig Worksheet