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Convert ((1)/(2)+2i)^(3) in the form of...

Convert ` ((1)/(2)+2i)^(3)` in the form of `a+ib`.

A

`-(47)/(2)-(13)/(2)i`

B

`-(47)/(8)-(13)/(2)i`

C

`-(47)/(8)-(13)/(4)i`

D

`-(47)/(4)-(13)/(4)i`

Text Solution

AI Generated Solution

The correct Answer is:
To convert \(\left(\frac{1}{2} + 2i\right)^3\) into the form \(a + ib\), we will use the binomial expansion formula for \((a + b)^3\). ### Step-by-Step Solution: 1. **Identify \(a\) and \(b\)**: Here, \(a = \frac{1}{2}\) and \(b = 2i\). 2. **Apply the binomial expansion**: The formula for \((a + b)^3\) is: \[ (a + b)^3 = a^3 + b^3 + 3a^2b + 3ab^2 \] 3. **Calculate each term**: - \(a^3 = \left(\frac{1}{2}\right)^3 = \frac{1}{8}\) - \(b^3 = (2i)^3 = 8i^3 = 8(-i) = -8i\) (since \(i^3 = -i\)) - \(3a^2b = 3\left(\frac{1}{2}\right)^2(2i) = 3 \cdot \frac{1}{4} \cdot 2i = \frac{3}{2}i\) - \(3ab^2 = 3\left(\frac{1}{2}\right)(2i)^2 = 3 \cdot \frac{1}{2} \cdot 4(-1) = -6\) 4. **Combine all terms**: Now, we combine all the calculated terms: \[ \left(\frac{1}{2} + 2i\right)^3 = \frac{1}{8} - 6 + \left(-8i + \frac{3}{2}i\right) \] 5. **Simplify the real part**: - The real part: \(\frac{1}{8} - 6 = \frac{1}{8} - \frac{48}{8} = -\frac{47}{8}\) 6. **Simplify the imaginary part**: - The imaginary part: \(-8i + \frac{3}{2}i = -8i + \frac{12}{2}i = -8i + 6i = -2i\) 7. **Final result**: Therefore, the expression in the form \(a + ib\) is: \[ -\frac{47}{8} - 2i \] ### Final Answer: \[ \left(\frac{1}{2} + 2i\right)^3 = -\frac{47}{8} - 2i \]

To convert \(\left(\frac{1}{2} + 2i\right)^3\) into the form \(a + ib\), we will use the binomial expansion formula for \((a + b)^3\). ### Step-by-Step Solution: 1. **Identify \(a\) and \(b\)**: Here, \(a = \frac{1}{2}\) and \(b = 2i\). 2. **Apply the binomial expansion**: ...
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NAGEEN PRAKASHAN-COMPLEX NUMBERS AND QUADRATIC EQUATION -MISCELLANEOUS EXERCISE
  1. Convert ((1)/(2)+2i)^(3) in the form of a+ib.

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  2. Evaluate : [i^(18)+(1/i)^(25)]^3

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  3. Prove that Re (z1 z2)= Re z1 Re z2 - Imz1 Imz2 ,

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  4. Reduce (1/(1-4i)-2/(1+i))((3-4i)/(5+i))to the standard form.

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  5. If (a+i b)/(c+i d)=x+i y , prove that (a-i b)/(c-i d)=x-i ya n d(a^2+b...

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  6. Convert the following in the polar form : (i) (1+7i)/((2-i)^2) (ii) (...

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  7. Solve the equation : 3x^2-4x+(20)/3=0

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  8. x^(2)-2x+(3)/(2)=0

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  9. Solve the equation :27 x^2-10 x+1=0

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  10. Solve the following quadratic: 21 x^2-28 x+10=0

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  11. If z1=2-i ,z2=1+i ,find |(z1+z2+1)/(z1-z2+i)|

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  12. If a + i b =((x+i)^2)/(2x^2+1),prove that a^2+b^2=((x^2+1)^2)/((2x^2+...

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  13. Let z1=2-i ,z2=-2+i. Find (i) Re ((z1z2)/( bar z1)) (ii) Im(1/(z1 bar...

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  14. Find the modulus and argument of the complex number (1+2i)/(1-3i).

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  15. Find the real numbers x\ a n d\ y , if (x-i y)(3+5i) is the conjugate ...

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  16. Find the modulus of (1+i)/(1-i)-(1-i)/(1+i).

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  17. If (x+i y)^3=u+i v ,then show that u/x+v/y=4(x^2-y^2).

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  18. If alpha and beta are different complex number with |beta|=1, then f...

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  19. Find the number of non-zero integral solutions of the equation |1-i|^...

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  20. If (a + i b) (c + i d) (e + i f) (g + i h) = A + i B, then show that (...

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  21. If ((1+i)/(1-i))^m=1, then find the least positive integral value of m...

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