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