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[AlephMobius]

How can you you solve the equation for a circle: (X-H)^2+(Y-k)^2=R^2 on the AFX 2 in terms of Y?

[BiTwhise]

You can't do it directly because of some strangeness with the cas program causing it to run out of memory.. so:

In CAS mode:

collect(expand((X-H)^2+(Y-K)^2),Y)
= Y^2-2KY+X^2+H^2-2HX+K^2
//subtract from this the terms involving y, and your left with:
X^2+H^2-2HX+K^2
//this will be your constant, assign it to a variable, say C
X^2+H^2-2HX+K^2->C
//now, solve the equation, using your the terms in your first answer involving Y + a constant (chose an empty variable):
solve(Y^2-2KY+A=R^2,Y)
//results:
eqn(1): Y = K-((4K^2-4(-R^2+A))^(1/2))/2
eqn(2): Y = K+((4K^2-4(-R^2+A))^(1/2))/2
//Substitute A for C, and you will have the full expresions
substitute(eqn(1),A=C)
=K-((-4(X^2-R^2+H^2-2HX+K^2)+4K^2)^(1/2))/2
substitute(eqn(2),A=C)
=K+((-4(X^2-R^2+H^2-2HX+K^2)+4K^2)^(1/2))/2