well, does ∇²f = 0?
Fxx = 2(y^2-x^2)/(x^2+y^2)^2
Fyy = 2(x^2-y^2)/(x^2+y^2)^2
so, what do you think?
Determine whether the function f(x,y)=ln(x^2 +y^2) is harmonic.
2 answers
No, but how do you know they equal zero or not?