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If omega (ne 1) is a cube root of unity ...

If `omega (ne 1)` is a cube root of unity and `(1 + omega)^(2017) = A + B omega`. Then A and B are respectively the numbers

A

0, 1

B

1, 1

C

1, 0

D

`-1, 1`

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The correct Answer is:
To solve the problem, we need to evaluate \((1 + \omega)^{2017}\) where \(\omega\) is a cube root of unity (and \(\omega \neq 1\)). The cube roots of unity satisfy the equation \(1 + \omega + \omega^2 = 0\). ### Step-by-step Solution: 1. **Identify the properties of cube roots of unity**: The cube roots of unity are \(1\), \(\omega\), and \(\omega^2\) where: \[ \omega^3 = 1 \quad \text{and} \quad 1 + \omega + \omega^2 = 0 \] From this, we can express \(1 + \omega\) as: \[ 1 + \omega = -\omega^2 \] 2. **Rewrite the expression**: We can rewrite \((1 + \omega)^{2017}\) using the expression we found: \[ (1 + \omega)^{2017} = (-\omega^2)^{2017} \] 3. **Simplify the power**: We can simplify \((-1)^{2017}\) and \((\omega^2)^{2017}\): \[ (-\omega^2)^{2017} = (-1)^{2017} \cdot (\omega^2)^{2017} = -(\omega^2)^{2017} \] Since \(\omega^3 = 1\), we can reduce the exponent \(2017\) modulo \(3\): \[ 2017 \mod 3 = 1 \quad \text{(since } 2017 = 3 \times 672 + 1\text{)} \] Thus, \((\omega^2)^{2017} = \omega^{2 \cdot 1} = \omega^2\). 4. **Combine the results**: Therefore, we have: \[ (1 + \omega)^{2017} = -\omega^2 \] 5. **Express in terms of \(A + B\omega\)**: We need to express \(-\omega^2\) in the form \(A + B\omega\). From the relation \(1 + \omega + \omega^2 = 0\), we can express \(\omega^2\) as: \[ \omega^2 = -1 - \omega \] Thus, \[ -\omega^2 = 1 + \omega \] 6. **Identify coefficients**: Now, we can identify \(A\) and \(B\): \[ A + B\omega = 1 + 1\omega \] Therefore, \(A = 1\) and \(B = 1\). ### Final Answer: Thus, the values of \(A\) and \(B\) are: \[ A = 1, \quad B = 1 \]
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MCGROW HILL PUBLICATION-COMPLEX NUMBERS -EXERCISE LEVEL 1
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  4. If omega is the complex cube root of unity then |[1,1+i+omega^2,omeg...

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  5. If omega is an imaginary cube root of unity, then (1-omega-omega^(2))^...

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  6. If |{:(6i,-3i,1),(4,3i,1),(20,3,i):}|=x+iy,i=sqrt(-1) then

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  7. If arg(z) lt 0, then find arg(-z) -arg(z).

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  8. If z1,z2, z3 are complex numbers such that |z1|=|z2|=|z3|=|1/z1+1/z2+1...

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  9. Let z1 and z2 be nth roots of unity which subtend a right angle at the...

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  11. Let omega = - (1)/(2) + i (sqrt3)/(2), then the value of the determina...

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  12. The inequality |z-i| lt |z + i| represents the region

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  13. Show that if iz^3+z^2-z+i=0, then |z|=1

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  14. If x + iy = (1)/(1-cos theta + 2 i sin theta), theta ne 2n pi, n in I,...

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  16. If z = 5 + t + isqrt(25 - t^(2)), (-5 le t le 5), then locus of z is a...

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  17. If omega is complex cube root of that 1/(a+omega)+1/(b+omega)+1/(c+ome...

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  18. if |z-iRe(z)|=|z-Im(z)| where i=sqrt(-1) then z lies on

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  19. If omega is a complex cube root of unity, then value of expression cos...

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