JEE Advanced · Mathematics · 3. Complex Numbers
Let be a cube root of unity. Then the minimum of the set distinct nonzero integers equals ________
- A 1
- B 2
- C 3
- D 4
Answer & Solution
Correct Answer
(C) 3
Step-by-step Solution
Detailed explanation
If is a complex number
Then
Now,
\(\left|a+b \omega+c \omega^2\right|^2=\left(a+b \omega+c \omega^2\right)(a+b \bar{\omega}\) \(+~c \bar{\omega}^2)\)
\(\left|a+b \omega+c \omega^2\right|^2=\frac{1}{2}[(a-b)^2+(b-c)^2\) \(+~(c-a)^2]\)
Now for this to be minimum
Take as are distinct and non-zero integers
Minimum of
Then
Now,
\(\left|a+b \omega+c \omega^2\right|^2=\left(a+b \omega+c \omega^2\right)(a+b \bar{\omega}\) \(+~c \bar{\omega}^2)\)
\(\left|a+b \omega+c \omega^2\right|^2=\frac{1}{2}[(a-b)^2+(b-c)^2\) \(+~(c-a)^2]\)
Now for this to be minimum
Take as are distinct and non-zero integers
Minimum of
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