Answer:
2 cis (7/6 pi)
Explanation:
r = sqrt( a^2 + b^2)
r = sqrt (-sqrt(3) )^2 + (-1)^2)
= sqrt(3 +1)
= sqrt(4)
= 2
theta = arctan (b/a)
theta = arctan (-1/-sqrt(3))
theta = 30
but this is in the third quardrant -a and -b
so add 180
theta = 210 degrees
convert this to radians
210 * pi/180 = 210/180 * pi = 21/18 * pi = 7/6 * pi
r cis (theta)
2 cis (7/6 pi)