JEE Advanced2019MathematicsComplex NumberActual
Let ω ≠ 1 be a cube root of unity. Then the minimum of the set a + b ω + c ω 2 2 : a ,   b , c distinct non – zero integers equals ________
Correct answer
0
Step-by-step solution
If z is a complex number Then | z | 2 = z z ¯ Now, a + b ω + c ω 2 2 = a + b ω + c ω 2 a + b ω + c ω 2 ¯ a + b ω + c ω 2 2 = a + b ω + c ω 2 a + b ω - + c ω - 2 i f   a ∈ R ⇒ a - = a z 1 z 2 ¯ = z - 1 z - 2 ω - = ω 2 ,    ω - 2 = ω a + b ω + c ω 2 2 = a + b ω + c ω 2 a + b ω 2 + c ω = a 2 + b 2 + c 2 - a b - b c - c a ∵   ω 3 = 1 ,  &