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12-78.
  1. Each labeled point on the graph below is either a maximum or a minimum. Homework Help ✎

    1. What are the period and amplitude of the graph?

    2. Write an equation for the graph.

    3. Use one of the labeled points to check your equation.

Period: How far is it between consecutive maximums or minimums?
Amplitude: How “tall” is the graph? Divide this answer by 2.

Find the vertical and horizontal shifts. For the vertical shift, what number is in the middle of 23 and −17?

Review the Math Notes box in Lesson 9.2.4 for help with the general equation of a sine or cosine graph.
In this case, it is more convenient to use cosine because you know a maximum point.

Substitute the values for each of the points into the equation to verify that it is correct.