The trigonometric form of the complex number consists of 2 parts:
i) Modulus (length)
ii) Argument (angle)
An interesting question : Can the argument be different?
Z = 5 (cos 450 + sin 300)
Is Z possible as the trigonometric form ?
If you comprehend the concept of vector, you will understand that having different angles in an expression carries no meaning.
The complex number Z represents a line of specific length pointing in a specific direction.
(Argand diagram can be drawn to reflect this.)
With a specific direction means only ONE angle is possible with reference to the positive Real horizontal axis.
Thus it is not possible to have the argument of different values in the trigonometric form.