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If (x+iy)^(2)-7+24i, then the value of (...

If `(x+iy)^(2)-7+24i`, then the value of `(7+sqrt(-576))^(1//2)-(7-sqrt(-576))^(1//2)`, is

A

`-6i`

B

`-3i`

C

`2i`

D

6

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The correct Answer is:
To solve the problem, we need to evaluate the expression \( (7 + \sqrt{-576})^{1/2} - (7 - \sqrt{-576})^{1/2} \). ### Step-by-Step Solution: 1. **Identify the square roots of the complex numbers**: \[ \sqrt{-576} = \sqrt{576} \cdot \sqrt{-1} = 24i \] Therefore, we can rewrite our expression as: \[ (7 + 24i)^{1/2} - (7 - 24i)^{1/2} \] 2. **Let \( z_1 = 7 + 24i \) and \( z_2 = 7 - 24i \)**: We need to find \( \sqrt{z_1} \) and \( \sqrt{z_2} \). 3. **Calculate the modulus and argument of \( z_1 \)**: - Modulus: \[ |z_1| = \sqrt{7^2 + 24^2} = \sqrt{49 + 576} = \sqrt{625} = 25 \] - Argument: \[ \theta_1 = \tan^{-1}\left(\frac{24}{7}\right) \] 4. **Express \( z_1 \) in polar form**: \[ z_1 = 25 \left( \cos(\theta_1) + i \sin(\theta_1) \right) \] 5. **Find the square root of \( z_1 \)**: \[ \sqrt{z_1} = \sqrt{25} \left( \cos\left(\frac{\theta_1}{2}\right) + i \sin\left(\frac{\theta_1}{2}\right) \right) = 5 \left( \cos\left(\frac{\theta_1}{2}\right) + i \sin\left(\frac{\theta_1}{2}\right) \right) \] 6. **Calculate the modulus and argument of \( z_2 \)**: - Modulus: \[ |z_2| = \sqrt{7^2 + (-24)^2} = \sqrt{49 + 576} = \sqrt{625} = 25 \] - Argument: \[ \theta_2 = \tan^{-1}\left(\frac{-24}{7}\right) \] 7. **Express \( z_2 \) in polar form**: \[ z_2 = 25 \left( \cos(\theta_2) + i \sin(\theta_2) \right) \] 8. **Find the square root of \( z_2 \)**: \[ \sqrt{z_2} = 5 \left( \cos\left(\frac{\theta_2}{2}\right) + i \sin\left(\frac{\theta_2}{2}\right) \right) \] 9. **Now substitute back into the expression**: \[ \sqrt{z_1} - \sqrt{z_2} = 5 \left( \cos\left(\frac{\theta_1}{2}\right) + i \sin\left(\frac{\theta_1}{2}\right) \right) - 5 \left( \cos\left(\frac{\theta_2}{2}\right) + i \sin\left(\frac{\theta_2}{2}\right) \right) \] 10. **Simplify the expression**: The real parts cancel out, and we are left with: \[ 5i \left( \sin\left(\frac{\theta_1}{2}\right) - \sin\left(\frac{\theta_2}{2}\right) \right) \] 11. **Final Result**: Since the imaginary parts yield \( 6i \) after evaluation, we conclude: \[ \text{The value is } 6i \]

To solve the problem, we need to evaluate the expression \( (7 + \sqrt{-576})^{1/2} - (7 - \sqrt{-576})^{1/2} \). ### Step-by-Step Solution: 1. **Identify the square roots of the complex numbers**: \[ \sqrt{-576} = \sqrt{576} \cdot \sqrt{-1} = 24i \] ...
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OBJECTIVE RD SHARMA-COMPLEX NUMBERS -Chapter Test
  1. If (x+iy)^(2)-7+24i, then the value of (7+sqrt(-576))^(1//2)-(7-sqrt(-...

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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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