What is the graph of r=a cos 4thetar=acos4θ?

1 Answer
Dec 30, 2014

Plotting the polar curve for 0<=theta<=2pi0θ2π I got:
enter image source here
I used Excel:
In the first column I put the angles in Radians;
In the second column is calculated a*cos(4theta)acos(4θ) for a=2a=2;

The next two columns contain the corresponding values of x and y to plot your equation on a rectangular coordinate system x,y.

To obtain the values in the x and y columns you must remember the relationship between polar (first two columns) and rectangular (second two columns) coordinates:
enter image source here

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