IF ω is a cube root of unity but not equal to 1 then minimum value of ∣ a+bw+cw2∣ (where a ,b, c are integers but not all equal) is
Let y=∣ a+bw+cw2∣
for y to be minimum y2 must be minimum.
y2=∣ a+bw+cw2∣2
y2=(a+bw+cw2)(a+bw+cw2)
=12[(a−b)2+(b−c)2+(c−a)2]
Since a,b and c are not equal at a time so minimum value of y2 occurs when any
two are same and third is differ by 1.
⇒ Minimum of y=1 (as a,b,c are integers)