How do you graph 5+8cos2x?

1 Answer
Bharat K.
May 2, 2015

We have f(x) = 5 + 8cos2x

Let's first breakdown the above equation.
cosx is pretty simple to plot as a function of x (just a sinusoidal wave). Now, cos2x plot looks exactly same as cosx but it varies two times faster than cosx (see the plots below).

cosx

graph{cos(x) [-10, 10, -2, 2]}

cos2x

graph{cos(2*x) [-10, 10, -2, 2]}

Multiplying cos2x by 8 gives you the following plot
(changes the amplitude of the curve)
8cos2x

graph{8cos(2x) [-10, 10, -10, 10]}

Finally, adding 5 to 8cos2x shifts the plot by 5 on the y-axis
5+8cos2x

graph{5+8cos(2x) [-10, 10, -6, 14]}

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