All I need help with is visualizing r^2=4cso2thadum
D degreeplus New member Joined Oct 7, 2006 Messages 24 Apr 3, 2007 #1 All I need help with is visualizing r^2=4cso2thadum
G galactus Super Moderator Staff member Joined Sep 28, 2005 Messages 7,216 Apr 3, 2007 #2 What is 'thadum'?. Surely you don't mean 'theta'?. :roll:
S soroban Elite Member Joined Jan 28, 2005 Messages 5,586 Apr 3, 2007 #3 Re: Agh need help on polar equations Hello, degreeplus! That Greek letter is "theta". . . I'll take a guess at what you meant . . . \(\displaystyle \begin{array}{cc}(1)\; & r^2\:=\:4\cos^2\theta \\ \\ \\ \\ & \text{or} \\ \\ \\ \\ (2)\; & r^2\:=\:4\cos2\theta\end{array}\) Click to expand... \(\displaystyle (1)\;r^2\:=\:4\cos^2\theta\) 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: \(\displaystyle \,(2,\,0),\2,\,\pi)\)
Re: Agh need help on polar equations Hello, degreeplus! That Greek letter is "theta". . . I'll take a guess at what you meant . . . \(\displaystyle \begin{array}{cc}(1)\; & r^2\:=\:4\cos^2\theta \\ \\ \\ \\ & \text{or} \\ \\ \\ \\ (2)\; & r^2\:=\:4\cos2\theta\end{array}\) Click to expand... \(\displaystyle (1)\;r^2\:=\:4\cos^2\theta\) 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: \(\displaystyle \,(2,\,0),\2,\,\pi)\)