Plot the point (3 comma StartFraction 7 pi Over 4 EndFraction )​, given in polar​ coordinates, and find other polar coordinates (r comma theta )of the point for which the following are true. ​(a) r greater than 0 comma negative 2 pi less than or equals theta less than 0 ​(b) r less than 0 comma 0 less than or equals theta less than 2 pi ​(c) r greater than 0 comma 2 pi less than or equals theta less than 4 pi