Agh need help on visualizing r^2=4cso2thadum

What is 'thadum'?. Surely you don't mean 'theta'?. :roll:
 
Re: Agh need help on polar equations

Hello, degreeplus!

That Greek letter is "theta".
. . I'll take a guess at what you meant . . .


\(\displaystyle \begin{array}{cc}(1)\; & r^2\:=\:4\cos^2\theta \\ \\ \\ \\ & \text{or} \\ \\ \\ \\
(2)\; & r^2\:=\:4\cos2\theta\end{array}\)

\(\displaystyle (1)\;r^2\:=\:4\cos^2\theta\)

We have: \(\displaystyle \:r\:=\:\pm2\cos\theta\)

\(\displaystyle r\:=\:2\cos\theta\) is a circle with radius 1
. . Its center is at \(\displaystyle (1,\,0)\)

\(\displaystyle r\:=\:-2\cos\theta\) is a circle with radius 1
. . Its center is at \(\displaystyle (1,\,\pi)\)

We have two unit circles, horizontally tangent at the origin.


\(\displaystyle (2)\;r^2 \:=\:4\cos2\theta\)

This is a two-leaf rose curve.
. . The ends of its 'petals' are: \(\displaystyle \,(2,\,0),\:(2,\,\pi)\)

 
Top