import sympy as sp
from IPython.display import display
z1,z2 = sp.symbols("z1 z2",complex=True)
PQ=sp.Abs(z2-z1)
display(PQ)
z1=-1+2*sp.I
z2=3-2*sp.I
PQ=sp.Abs(z2-z1)
display(PQ)