Illuminations: Trigonometric Graphing

Trigonometric Graphing


Explore the amplitude, period, and phase shift by examining the graphs of various trigonometric functions. Students can select values to use within the function to explore the resulting changes in the graph.

Instructions

 
Using the pull-down menus, select values for a, b, c, and d. The graph of the function will be updated automatically.

Selecting the "show base function" option causes the basic function (with a = b = 1 and c = d = 0) to be graphed in red. The function with other values for the parameters appears in green. (Note that if the parameters of the base function are the same as the values for your function, the graphs will be superimposed.)

Choose "degrees" to graph the function in degree measure, and choose "radians" to graph the function in radian measure.

Exploration

 
Change the values of a, b, c and d one at a time.
  • What effect does changing the value of a have on the graph?
  • What effect does changing the value of b have on the graph?
  • What effect does changing the value of c have on the graph?
  • What effect does changing the value of d have on the graph?

Given what you discovered, predict what the graph of 8 cos(2x – 30°) + 7 would look like. What are its amplitude and period?

  

NCTM Resources

Navigating through Algebra in 9‑12

National Council of Teachers of Mathematics Thinkfinity Verizon Foundation
© 2000 National Council of Teachers of Mathematics
Use of this Web site constitutes acceptance of the Terms of Use