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5.5 Circular Functions: Graphs and Properties Tues Jan 14. Do Now Evaluate 1) Sin pi/2 2) Cos 2pi 3) Tan pi/4. Quiz Review. Retakes by next Wed. Circular Functions. The domains of the trigonometric functions have been sets of angles or rotations.
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5.5 Circular Functions: Graphs and PropertiesTues Jan 14 Do Now Evaluate 1) Sin pi/2 2) Cos 2pi 3) Tan pi/4
Quiz Review • Retakes by next Wed
Circular Functions • The domains of the trigonometric functions have been sets of angles or rotations. • Trigonometric functions with domains composed of real numbers (radians) are called circular functions
Basic Circular Functions • With respect to S radians,
Reflections on the Unit Circle • Because the unit circle is symmetric, we can use the coordinates of one point on the unit circle to find coordinates of its reflections • (Draw unit circle with point x,y )
Ex1 • The point (3/5, 4/5) lies on the unit circle. Find its reflections across the x-axis, y-axis, and origin
Finding Function Values • Knowing the coordinates of only a few points on the unit circle + reflections allows you to find many trig values
Ex • Find each of the following using reflections • 1) • 2) • 3)
Calculator and Radians • When working in radians, make sure the calculator is set to radians mode! • MODE -> RADIANS should be highlighted
Graphs of Sine and Cosine Functions • One characteristic about circular functions is that they repeat, or oscillate • Since circular functions travel on a circle, they tend to repeat every revolution
Graph of y = sin x • Let’s look at the y-coordinate on the unit circle
Graph of y = cos x • Let’s look at the x-coordinate of the unit circle
Domain and Range • The domain and range of both sine and cosine functions are the same • Domain = All real numbers • Range = [-1, 1]
Period of sine and cosine • A function with a repeating pattern is called periodic. All trig graphs are periodic. • The period of y = sin x and y = cos x is 2pi
Amplitude • The amplitude of a periodic function is defined as one half of the distance between its maximum and minimum values • You can calculate this by dividing the range by 2 • The amplitude of y = sin x and y = cos x is 1
Symmetry • Sin (-x) = - sin x • The sine function is odd • Cos (-x) = cos x • The cosine function is even
Closure • Describe the graphs of the sine and cosine functions. How are they similar? Different? • HW: p.505 #1-47 odds
5.5 Sine and Cosine Graph ReviewWed Jan 15 • Do Now • Evaluate • 1) • 2)
(If time) The other 4 trig graphs • Tan x and cot x • These 2 graphs have asymptotes
Sec x and csc x • These 2 also have asymptotes
Closure • Why are the other 4 trig graphs different than sine and cosine? • SGO quiz tomorrow