# Trig Review Part 3

Taught by YourMathGal
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Part of video series
Meets NCTM Standards:
Lesson Summary:

In this trigonometry lesson, the instructor reviews graphing y = cos(x/3) and y = 2sin(pi*x/3), as well as stating their respective periods and amplitudes. The lesson also includes solutions to a review for a trigonometry test. The period of y = cos(x/3) is found by dividing 2pi by the coefficient of x, while the amplitude is simply the absolute value of the coefficient. For y = 2sin(pi*x/3), the period is calculated by dividing the period of sine (2pi) by the coefficient of x, while the amplitude is the absolute value of 2. Overall, the lesson provides a comprehensive review of these important trigonometric concepts.

Lesson Description:

Graphing y = cos(x/3) and stating period. Graphing y = 2sin(pi*x/3) and stating amplitude and period. Solutions to a Review for a Trigonometry Test for a class. . See pdf on that site under Trig, special videos.

More free YouTube videos by Julie Harland are organized at http://yourmathgal.com

Questions answered by this video:
• How do you graph y = cos(x/3)?
• How do you find the amplitude and period of y = cos(x/3)?
• How do you graph y = 2*sin(pi*x/3)?
• How do you find the amplitude and period of y = 2*sin(pi*x/3)?
• #### Staff Review

• Currently 4.0/5 Stars.
This lesson shows more examples of graphing trig functions. Also, you will learn how to find the amplitude and period of trig functions. It is usually easiest to graph the parent function, such as cos x or sin x, and then modify it based on the coefficients. This is a great place to learn or review how to graph trig functions.