Q.

If |z|=1 and z±1, then all the values of z1-z2 lie on                 [2007]

1 a line not passing through the origin  
2 |z|=2  
3 the x-axis  
4 the y-axis  

Ans.

(4)

Given: |z|=1 and z±1

To find the locus of ω=z1-z2

Now, ω=z1-z2=zzz¯-z2            [ |z|=1|z|2=zz¯=1]

=1z¯-z=purely imaginary number

 ω must lie on y-axis.