SOLUTION: If z1 = 4cis300° and z2 = 2cis30° , find z1z2 in its POLAR FORM: rcis(theta).

The rule of multiplication of complex numbers, written in polar form, is THIS:


    +------------------------------------------------------+
    |    The product of complex numbers is the product     | 
    |    of their modules and the sum of their arguments.  |
    +------------------------------------------------------+


or, in mathematical form

    r*cis(a) * R*cis(b) = rR*cis(a+b)



In your problem

    z1 * z2 = 4cis(300°)*2cis(30°) = 8cis(330°).