I need to prove that there is *no* solution to the equation:
x^2 + y^2 = 3(mod4)
I tried to assume there is a solution, meaning, there are X,Y in Z so that:
x^2 + y^2 = 3 + 4*k.
I tried to reach a contradiction, but alas, I did not succeed :-\
Thank you very much, in advance!