The Sine Function
Warm up
Press the play button or move the slider.
What is the x-value of the red point?
What is the y-value of the red point?
Tracing the red points results in the graph of .
This sine function relates an angle measure in radians to the y-value of a point on the unit circle.
What type of function is the sine function?
Transforming Sine Functions
Move the sliders.
How does changing the slider for a affect the graph of this sine function?
What happens to the graph when a is negative?
How does changing the slider for b affect the graph of this sine function?
Key Concept (Take Note!)
For the periodic function , where , , and is an angle in radians:
- The amplitude of the function is .
- The function has cycles between 0 and .
- The period of the function is .
Which function would have an amplitude of 4?
Which function would have a period of pi?
Sketching a Sine Function
- Draw an x-axis from 0 to the period of the function. Divide the period into 4 pieces.
- Draw a y-axis from the amplitude to the opposite of the amplitude.
- Use a five-point summary to sketch the graph of a sine function:
Sketch the graph of .
Write an equation for the sine function shown above.
Exercise!
pg. 848 - 849
#15 - 30 all, 47,
48