http://www.wolframalpha.com/input/?i=r^2%3Dcos+(2theta)
http://www.wolframalpha.com/input/?i=r%3Dcos+%28theta%2F2%29
http://www.wolframalpha.com/input/?i=r%3Dcos+(theta/3)
http://www.wolframalpha.com/input/?i=r%3D1%2B2+cos+(theta)
http://www.wolframalpha.com/input/?i=r%3D2%2Bsin(3thetA)
http://www.wolframalpha.com/input/?i=r%3D1%2B2sin(3theta)