Question

If z1 & z2 are two complex numbers and |z1 +z2| = |z1| + |z2| . Then proved that arg z1 = arg z2

Answer 1

|Z1+Z2| ≤|Z1|+|Z2| that means.. it is given that they are equal .. so in argand plane.. they must lie on the same line.. joining z1 z2 and origin.. hence they have the same argument