Grafeq is incredibly easy to use.
Just type in the graph or graphs you would like, and it quickly generates it!
Download it here. http://www.peda.com/grafeq/
(click each image to see larger version)
Inequalities (you can choose the colors too!)
Want to restrict the domain? NO PROBLEM (just press tab to add conditions)
NOTE: grafeq automatically inserts the theta symbol when you type "theta" (same for all greek letters)
r = 3sin(4theta)
0 < theta < pi