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

If `omega(ne 1)` be a cube root of unity and `(1+omega^(2))^(n)=(1+omega^(4))^(n)`, then the least positive value of n, is

A

2

B

3

C

5

D

6

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To solve the equation \((1 + \omega^2)^n = (1 + \omega^4)^n\) where \(\omega\) is a cube root of unity, we can follow these steps: ### Step 1: Understand the properties of cube roots of unity The cube roots of unity are given by: 1. \(\omega^3 = 1\) 2. \(1 + \omega + \omega^2 = 0\) From the second property, we can express \(\omega^2\) as: \[ \omega^2 = -1 - \omega \] ### Step 2: Rewrite the equation We start from the equation: \[ (1 + \omega^2)^n = (1 + \omega^4)^n \] Since \(\omega^4 = \omega\) (because \(\omega^4 = \omega^{3+1} = \omega\)), we can rewrite the equation as: \[ (1 + \omega^2)^n = (1 + \omega)^n \] ### Step 3: Simplify the expression We can divide both sides by \((1 + \omega)^n\) (assuming \(1 + \omega \neq 0\)): \[ \frac{1 + \omega^2}{1 + \omega} = 1 \] This implies: \[ 1 + \omega^2 = 1 + \omega \] ### Step 4: Solve for \(\omega\) Subtracting 1 from both sides gives: \[ \omega^2 = \omega \] This is only true if \(\omega = 0\) or if \(\omega\) is a specific value. However, since \(\omega\) is a cube root of unity, we can check the values of \(\omega\): - If \(\omega = 1\), then \(\omega^2 = 1\) (not valid since \(\omega \neq 1\)). - If \(\omega = \omega\), then \(\omega^2 = \omega^2\) (valid). ### Step 5: Analyze the implications Since \(1 + \omega^2\) and \(1 + \omega\) are equal, we can conclude that the equality holds for certain values of \(n\). ### Step 6: Find the least positive value of \(n\) The equality \((1 + \omega^2)^n = (1 + \omega)^n\) holds when: \[ \left(\frac{1 + \omega^2}{1 + \omega}\right)^n = 1 \] This means that the ratio must be a root of unity. The least positive value of \(n\) that satisfies this condition is when \(n\) is a multiple of 3, since the cube roots of unity repeat every 3. Thus, the least positive value of \(n\) is: \[ \boxed{3} \]

To solve the equation \((1 + \omega^2)^n = (1 + \omega^4)^n\) where \(\omega\) is a cube root of unity, we can follow these steps: ### Step 1: Understand the properties of cube roots of unity The cube roots of unity are given by: 1. \(\omega^3 = 1\) 2. \(1 + \omega + \omega^2 = 0\) From the second property, we can express \(\omega^2\) as: ...
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OBJECTIVE RD SHARMA-COMPLEX NUMBERS -Chapter Test
  1. If omega(ne 1) be a cube root of unity and (1+omega^(2))^(n)=(1+omega^...

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  2. The locus of the center of a circle which touches the circles |z-z1|=a...

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  3. If n1, n2 are positive integers, then (1 + i)^(n1) + ( 1 + i^3)^(n1) +...

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  4. The modulus of sqrt(2i)-sqrt(-2i) is

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  5. Prove that the triangle formed by the points 1,(1+i)/(sqrt(2)),a n di ...

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  6. The value of (1+isqrt(3))/(1-isqrt(3))^(6)+(1-isqrt(3))/(1+isqrt(3))^(...

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  7. If alpha+ibeta=tan^(-1) (z), z=x+iy and alpha is constant, the locus o...

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  8. If cosA+cosB+cosC=0,sinA + sinB + sinC=0and A+B+C=180^0, then the valu...

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  9. The value of the expression 1.(2-omega).(2-omega^2)+2.(3-omega)(3-omeg...

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  10. The value of the expression (1+1/omega)(1+1/omega^(2))+(2+1/omega)(2+...

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  11. The condition that x^(n+1)-x^(n)+1 shall be divisible by x^(2)-x+1 is ...

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  12. The expression (1+i)^(n1)+(1+i^(3))^(n(2)) is real iff

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  13. |{:("6i " "-3i " "1" ),("4 " " 3i" " -1"),("20 " "3 " " i"):}|=x+iy th...

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  14. The centre of a square ABCD is at z0dot If A is z1 , then the centroid...

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  15. If cosalpha+2cosbeta+3cosgamma=sinalpha+2sinbeta+3singamma=0 and alpha...

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  16. If cosalpha+2cosbeta+3cosgamma=sinalpha+2sinbeta+3singamma=0 and alpha...

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  17. Sum of the series sum(r=0)^n (-1)^r ^nCr[i^(5r)+i^(6r)+i^(7r)+i^(8r)] ...

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  18. If az(1)+bz(2)+cz(3)=0 for complex numbers z(1),z(2),z(3) and real num...

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  19. If 2z1-3z2 + z3=0, then z1, z2 and z3 are represented by

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  20. Re((z+4)/(2z-1)) = 1/2, then z is represented by a point lying on

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  21. The vertices of a square are z1,z2,z3 and z4 taken in the anticlockwis...

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