1. As a pair of functions

To plot the circle as a pair of functions, we need to solve for . We can do this easily in our heads, (at least I hope you can) or ask maple:

> circfuncs:= {solve(circleEqn,y)};

Since we need a specific choice for the center and radius for this to work, let's substitute in :

> mycircfuncs:= subs(a=2,b=1,R=3,circfuncs);

> plot(mycircfuncs,x=-1..5,scaling=constrained);