The amplitude of the sine and cosine functions is the vertical distance between the sinusoidal axis and the maximum or minimum value of the function. In relation to sound waves, amplitude is a measure of how loud something is.
What is the most common mistake made when graphing the amplitude of a sine wave?
Amplitude of Sinusoidal Functions
The general form a sinusoidal function is:
The cosine function can just as easily be substituted and for many problems it will be easier to use a cosine equation. Since both the sine and cosine waves are identical except for a horizontal shift, it all depends on where you see the wave starting.
Watch the portion of this video discussing amplitude:
Write a cosine equation for each of the following functions.
Note that amplitude itself is always positive.
A Ferris wheel with radius 25 feet sits next to a platform. The ride starts at the platform and travels down to start. Model the height versus time of the ride.
1. Explain how to find the amplitude of a sinusoidal function from its equation.
2. Explain how to find the amplitude of a sinusoidal function from its graph.
Find the amplitude of each of the following functions.
Sketch each of the following functions.
To see the Review answers, open this PDF file and look for section 5.3.