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If i=sqrt(-1), then 4+5(-1/2+(isqrt(3))...

If `i=sqrt(-1)`, then `4+5(-1/2+(isqrt(3))/(2))^(334)+3(-1/2+(isqrt(3))/(2))^(365)`is equal to

A

`1-isqrt(3)`

B

`-1+isqrt(3)`

C

`isqrt(3)`

D

`-isqrt(3)`

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The correct Answer is:
To solve the expression \( 4 + 5\left(-\frac{1}{2} + \frac{i\sqrt{3}}{2}\right)^{334} + 3\left(-\frac{1}{2} + \frac{i\sqrt{3}}{2}\right)^{365} \), we first recognize that \( -\frac{1}{2} + \frac{i\sqrt{3}}{2} \) can be expressed in polar form. ### Step 1: Identify the complex number The complex number \( z = -\frac{1}{2} + \frac{i\sqrt{3}}{2} \) can be written in polar form. - The modulus \( r \) is given by: \[ r = \sqrt{\left(-\frac{1}{2}\right)^2 + \left(\frac{\sqrt{3}}{2}\right)^2} = \sqrt{\frac{1}{4} + \frac{3}{4}} = \sqrt{1} = 1 \] - The argument \( \theta \) is: \[ \theta = \tan^{-1}\left(\frac{\frac{\sqrt{3}}{2}}{-\frac{1}{2}}\right) = \tan^{-1}(-\sqrt{3}) = \frac{2\pi}{3} \text{ (in the second quadrant)} \] Thus, we can express \( z \) as: \[ z = e^{i\frac{2\pi}{3}} \] ### Step 2: Calculate the powers of \( z \) Now, we compute \( z^{334} \) and \( z^{365} \): - Using De Moivre's theorem: \[ z^{n} = r^n e^{in\theta} \] Since \( r = 1 \): \[ z^{334} = e^{i\frac{2\pi}{3} \cdot 334} = e^{i\frac{668\pi}{3}} = e^{i(222\pi + \frac{2\pi}{3})} = e^{i\frac{2\pi}{3}} = z \] (Since \( e^{i2\pi k} = 1 \) for any integer \( k \)) For \( z^{365} \): \[ z^{365} = e^{i\frac{2\pi}{3} \cdot 365} = e^{i\frac{730\pi}{3}} = e^{i(243\pi + \frac{1\pi}{3})} = e^{i\frac{\pi}{3}} = \frac{1}{2} + \frac{i\sqrt{3}}{2} \] ### Step 3: Substitute back into the expression Now we substitute back into the original expression: \[ 4 + 5z + 3\left(\frac{1}{2} + \frac{i\sqrt{3}}{2}\right) \] Calculating \( 3\left(\frac{1}{2} + \frac{i\sqrt{3}}{2}\right) \): \[ 3\left(\frac{1}{2} + \frac{i\sqrt{3}}{2}\right) = \frac{3}{2} + \frac{3i\sqrt{3}}{2} \] Now we combine everything: \[ 4 + 5\left(-\frac{1}{2} + \frac{i\sqrt{3}}{2}\right) + \left(\frac{3}{2} + \frac{3i\sqrt{3}}{2}\right) \] Calculating \( 5z \): \[ 5z = 5\left(-\frac{1}{2} + \frac{i\sqrt{3}}{2}\right) = -\frac{5}{2} + \frac{5i\sqrt{3}}{2} \] ### Step 4: Combine all parts Now we combine: \[ 4 - \frac{5}{2} + \frac{3}{2} + \left(\frac{5i\sqrt{3}}{2} + \frac{3i\sqrt{3}}{2}\right) \] Calculating the real part: \[ 4 - \frac{5}{2} + \frac{3}{2} = 4 - 1 = 3 \] Calculating the imaginary part: \[ \frac{5i\sqrt{3}}{2} + \frac{3i\sqrt{3}}{2} = \frac{8i\sqrt{3}}{2} = 4i\sqrt{3} \] ### Final Result Thus, the final result is: \[ 3 + 4i\sqrt{3} \]

To solve the expression \( 4 + 5\left(-\frac{1}{2} + \frac{i\sqrt{3}}{2}\right)^{334} + 3\left(-\frac{1}{2} + \frac{i\sqrt{3}}{2}\right)^{365} \), we first recognize that \( -\frac{1}{2} + \frac{i\sqrt{3}}{2} \) can be expressed in polar form. ### Step 1: Identify the complex number The complex number \( z = -\frac{1}{2} + \frac{i\sqrt{3}}{2} \) can be written in polar form. - The modulus \( r \) is given by: \[ r = \sqrt{\left(-\frac{1}{2}\right)^2 + \left(\frac{\sqrt{3}}{2}\right)^2} = \sqrt{\frac{1}{4} + \frac{3}{4}} = \sqrt{1} = 1 ...
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OBJECTIVE RD SHARMA-COMPLEX NUMBERS -Chapter Test
  1. If i=sqrt(-1), then 4+5(-1/2+(isqrt(3))/(2))^(334)+3(-1/2+(isqrt(3))/...

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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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