Question

Which of the following is correct for any two complex numbers z1 and z2?

(A) |z1z2| = |z1||z2|

(B) arg (z1z2) = arg (z1). arg (z2)

(C) |z1 +z2| = |z1| + |z2|

(D) |z1 +z2| ≥ |z1| - |z2|

Answer 1

Answer is (A)

Clearly, |z1z2| = |z1||z2|