Since Sequential Impulse remove constants, How do I use a constraint that has one?

So I've written a constraint for keeping an object at a fixed distance from a fixed point,you can call circular constraint (it is in 2D), so the math equation for this is : (x-2)^2+(y-2^2)=1,assuming the fixed point coords are (2,2) and the fixed distance is 1,anyway when I differentiate it , it removes the constant which is very important for the constraint , and once I apply it, it assumes that the fixed distance is the distance from my object and the fixed point , here is the solver,I'm using a very basic …