If (z1,z2) and (z3,z4) are two pairs of conjugate complex numbers, then show that
argz1z3+argz2z4=0.
If z1,z2 and z3,z4 are two pairs of conjugate complex numbers, prove that arg(z1z4)+arg(z2z3)=0.
If z1,z2 are conjugate complex numbers, and z3,z4 are also conjugate, then show that
argz3z2+argz1z4=0.