2012/017) Z1, z2 & z3 are 3 complex no.'s that lie on a circle w/ centre (0,0). show that the reciprocals are in a circle

z1 = r cis t1
z2 = r cis t2
z3 = r cis t3

as they are in a circle with center (0,0)

1/z1 = 1/r cis (- t1)
1/z2 = 1/r cis (- t2)
1/z3 = 1/r cis (- t3)

they are also in a circle or radius 1/r