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Warm up…. Draw the special right triangles… Find the side lengths for a triangle of radius 1:. Section 4.2 THE UNIT CIRCLE. The Unit Circle:. The set of points at a distance 1 from the origin, a circle of radius 1. x 2 + y 2 = 1.
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Warm up…. • Draw the special right triangles… • Find the side lengths for a triangle of radius 1:
Section 4.2 THE UNIT CIRCLE
The Unit Circle: The set of points at a distance 1 from the origin, a circle of radius 1 x2 + y2 = 1 Terminal Points: the point (x, y) from a distance around a circle starting from (1,0 )
A circle is symmetric with respect to? y = x Therefore, we can find other terminal points on this unit circle.
Can you fill in the missing degree values and correct coordinates?
Definition of the trigonometric functions: • Let t be any real number and let P(x,y) be the terminal point on the unit circle determined by t then:
4.2 – Day 2 Warm Up • Without using your notebook, calculator, friends, etc. Fill out a blank unit circle. • If you talk or cheat you are disqualified! *A correctly completed UNIT CIRCLE will earn a 5 pt pass!!!
When functions behave in a repetitive (or cyclic) manner, they are called PERIODIC. f( t + c) = f(t) “c” is the period…… try to always use 2π *this will help you evaluate numbers when they are not on the unit circle (ex) Evaluate sin 13π 6
Some more practice evaluating: More practice…. Pg . 278 # 30 – 36 even
HW DAY 2pg. 278 #’s 4, 6, 10, 14-28 even, 29-39 odd*Memorize Unit Circle and Trig Functions!!!!
Even and Odd properties of Trig Functions: • Even: Cosine and Secant cos (-t) = cos (t) sec (-t)=sec (t) • Odd: sine, cosecant, tangent, and cotangent sin (-t) = - sin t csc (-t) = -csc t tan (-t) = - tan t cot (-t) = - cot t
Last but not least…. • Of course you can evaluate using your calculator!! The steps, if you don’t remember are on page 277 at the bottom!!
Some practice/HW – DAY 3 • Pg. 278 #’s 39 – 52 all, 53, 55, and 58