My target is to find a center of a circle that approximate a set of dots
i want to find minimum of a function: $$\sum_{i=0}^N (\sqrt{(x_i - a)^2 + (y_i - b)^2} - R)^2$$
this function represent an error of a my approximation of a set a dots on a plane with a circle.
I did a bit of a googling and find that Gradient Descent is a decent method for a numerical searching for a minimum of function.
But i have a trouble with understanding how i should correcnt my A,B,R with partial derrivative, when i have function of summ.
picture related for better explanation of my problem: https://i.stack.imgur.com/vSsZU.jpg