Find the modulus of each of the following complex numbers and hence express each of them in polar form: (sin 120° – i cos 120°)

= sin(90° + 30° ) - icos(90° + 30°)


= cos30° + isin30°


Since, sin(90°+ α) = cosα


And cos(90° + α) = -sinα



hence it is of the form



Therefore r = 1


Hence its modulus is 1 and argument is


1