Let z∈C be such that Re(z2) = 0, then
|Re(z)|+Im(z)=0
|Re(z)|=|Im(z)|
Re(z)+|Im(z)|=0
Re(z)=0 or Im(z)=0
Let z=x+iy, then z2=x2−y2+2ixy
∴Rez2=0⇒x2−y2=0
⇒|Re(z)|=|Im(z)|