Step-by-step explanation:
If our r is negative, then we must add pi from the angle.
[tex](4, \frac{\pi}{2} )[/tex]
goes to
[tex]( - 4, \frac{\pi}{2} + \pi) = ( - 4, \frac{3\pi}{2} )[/tex]
If our r is Positve, we can add 2 pi to the angle.
[tex](4, \frac{\pi}{2} + 2\pi) = (4, \frac{5\pi}{2} )[/tex]
