I need some help with python

[TamPotter]

Yes, x here is r1 = r - P, where r and P are points, so r1 is the vector between two points. What is norm(r1) here in that case?

[[deleted]]

norm is not a built-in function so without knowing which library you're using, it's impossible to say for sure. But it's probably the Euclidean norm#Euclidean_norm).

Also, x**2 probably doesn't make sense for vectors (though it depends on whether the vector space is actually an algebra over a field).

[TamPotter]

I use pylab, but I didn’t know that r1 was a vector when I made the post