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Express the following in the form a+bi ...

Express the following in the form a+bi
`(-2-(1)/(3)i)^(3)`

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To express the complex number \((-2 - \frac{1}{3}i)^{3}\) in the form \(a + bi\), we will follow these steps: ### Step 1: Rewrite the expression We start with the expression: \[ (-2 - \frac{1}{3}i)^{3} \] We can rewrite this as: \[ (-1)^{3} \cdot (2 + \frac{1}{3}i)^{3} = - (2 + \frac{1}{3}i)^{3} \] ### Step 2: Use the binomial expansion Using the binomial expansion for \((A + B)^{3}\), where \(A = 2\) and \(B = \frac{1}{3}i\): \[ (A + B)^{3} = A^{3} + B^{3} + 3AB(A + B) \] Substituting \(A\) and \(B\): \[ (2 + \frac{1}{3}i)^{3} = 2^{3} + \left(\frac{1}{3}i\right)^{3} + 3 \cdot 2 \cdot \frac{1}{3}i \cdot (2 + \frac{1}{3}i) \] ### Step 3: Calculate each term Calculating \(2^{3}\): \[ 2^{3} = 8 \] Calculating \(\left(\frac{1}{3}i\right)^{3}\): \[ \left(\frac{1}{3}i\right)^{3} = \frac{1}{27}i^{3} = \frac{1}{27}(-i) = -\frac{1}{27}i \] Calculating \(3 \cdot 2 \cdot \frac{1}{3}i \cdot (2 + \frac{1}{3}i)\): \[ 3 \cdot 2 \cdot \frac{1}{3}i = 2i \] Now, we need to calculate \(2i(2 + \frac{1}{3}i)\): \[ 2i \cdot 2 + 2i \cdot \frac{1}{3}i = 4i + \frac{2}{3}i^{2} \] Since \(i^{2} = -1\): \[ \frac{2}{3}i^{2} = -\frac{2}{3} \] So, we have: \[ 2i(2 + \frac{1}{3}i) = 4i - \frac{2}{3} \] ### Step 4: Combine all terms Now we combine all the terms: \[ (2 + \frac{1}{3}i)^{3} = 8 - \frac{1}{27}i + 4i - \frac{2}{3} \] Combining the real parts: \[ 8 - \frac{2}{3} = \frac{24}{3} - \frac{2}{3} = \frac{22}{3} \] Combining the imaginary parts: \[ -\frac{1}{27}i + 4i = -\frac{1}{27}i + \frac{108}{27}i = \frac{107}{27}i \] ### Step 5: Final expression Thus, we have: \[ (2 + \frac{1}{3}i)^{3} = \frac{22}{3} + \frac{107}{27}i \] So, \[ - (2 + \frac{1}{3}i)^{3} = -\frac{22}{3} - \frac{107}{27}i \] ### Final Answer The expression in the form \(a + bi\) is: \[ -\frac{22}{3} - \frac{107}{27}i \]
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ICSE-COMPLEX NUMBERS-Chapter Test
  1. Express the following in the form a+bi (-2-(1)/(3)i)^(3)

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  2. Find the square root of 5-12i

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  3. Find the locus of a complex number z=x +yi, satisfying the relation |z...

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  4. Express (13i)/(2-3i) in the form A + Bi

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  5. If z= x +yi and (|z-1-i|+4)/(3|z-1-i|-2)=1, show that x^(2) + y^(2) -2...

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  6. If omega and omega^(2) are cube roots of unity, prove that (2- omega +...

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  7. If z(1), z(2) in C (set of complex numbers), prove that |z(1) + z(2)| ...

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  8. If z = x + yi, omega = (2-iz)/(2z-i) and |omega|=1, find the locus of ...

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  9. Simplify: (1- 3omega + omega^(2)) (1 + omega- 3omega^(2))

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  10. Find the locus of z satisfying |(z-3)/(z+1)|=3 in the complex plane.

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  11. Given that (2 sqrt3 cos 30^(@) - 2i sin 30^(@))/(sqrt2 (cos 45^(@) + i...

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  12. Simplify : (1- omega) (1- omega^(2)) (1- omega^(4)) (1- omega^(8))

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  13. Find the locus of a complex number z= x + yi, satisfying the relation ...

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  14. Find the real values of x and y satisfying the equality (x-2 + (y-3)i)...

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  15. If i= (sqrt-1), prove that following (x+1+i) (x+ 1-i) (x-1-i) (x-1+ i)...

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  16. If z= x + yi and |2z + 1| = |z- 2i|, show that 3(x^(2) + y^(2)) + 4(x-...

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  17. Find the amplitude of the complex number "sin" (6pi)/(5) + i (1- "cos"...

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  18. Express (1- 2i)/(2+i) + (3+i)/(2-i) in the form a + bi

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  19. Find the value of x and y given that (x + yi) (2-3i)=4+i

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  20. If the ratio (z-i)/(z-1) is purely imaginary, prove that the point z l...

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  21. If (-2 + sqrt-3) (-3 + 2 sqrt-3) = a + bi, find the real numbers a and...

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