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The origin and the roots of the equation `z^2 + pz + q = 0` form an equilateral triangle If -

A

`p^(2)=q`

B

`p^(2)=3q`

C

`p^(2)=3p`

D

`q^(2)=p`

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The correct Answer is:
To solve the problem, we need to establish the relationship between the coefficients of the quadratic equation \( z^2 + pz + q = 0 \) and the condition that the origin and the roots of the equation form an equilateral triangle. ### Step-by-Step Solution: 1. **Identify the Roots and Origin**: Let the roots of the quadratic equation be \( z_1 \) and \( z_2 \). The origin is represented by \( z_3 = 0 \). Therefore, the vertices of the equilateral triangle are \( z_1, z_2, \) and \( z_3 \). 2. **Use Vieta's Formulas**: According to Vieta's formulas for the quadratic equation \( z^2 + pz + q = 0 \): - The sum of the roots \( z_1 + z_2 = -p \) - The product of the roots \( z_1 z_2 = q \) 3. **Equilateral Triangle Property**: For three points \( z_1, z_2, z_3 \) to form an equilateral triangle, the following condition must hold: \[ z_1^2 + z_2^2 + z_3^2 = z_1 z_2 + z_2 z_3 + z_3 z_1 \] Substituting \( z_3 = 0 \): \[ z_1^2 + z_2^2 + 0^2 = z_1 z_2 + z_2 \cdot 0 + 0 \cdot z_1 \] This simplifies to: \[ z_1^2 + z_2^2 = z_1 z_2 \] 4. **Express \( z_1^2 + z_2^2 \)**: We can express \( z_1^2 + z_2^2 \) using the identity: \[ z_1^2 + z_2^2 = (z_1 + z_2)^2 - 2z_1 z_2 \] Substituting \( z_1 + z_2 = -p \) and \( z_1 z_2 = q \): \[ z_1^2 + z_2^2 = (-p)^2 - 2q = p^2 - 2q \] 5. **Set Up the Equation**: Now we have: \[ p^2 - 2q = q \] Rearranging gives: \[ p^2 - 3q = 0 \] or \[ p^2 = 3q \] 6. **Conclusion**: Therefore, the condition that the origin and the roots of the equation \( z^2 + pz + q = 0 \) form an equilateral triangle is given by: \[ p^2 = 3q \] ### Final Answer: The condition is \( p^2 = 3q \).

To solve the problem, we need to establish the relationship between the coefficients of the quadratic equation \( z^2 + pz + q = 0 \) and the condition that the origin and the roots of the equation form an equilateral triangle. ### Step-by-Step Solution: 1. **Identify the Roots and Origin**: Let the roots of the quadratic equation be \( z_1 \) and \( z_2 \). The origin is represented by \( z_3 = 0 \). Therefore, the vertices of the equilateral triangle are \( z_1, z_2, \) and \( z_3 \). 2. **Use Vieta's Formulas**: ...
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OBJECTIVE RD SHARMA ENGLISH-COMPLEX NUMBERS -Chapter Test
  1. The origin and the roots of the equation z^2 + pz + q = 0 form an equi...

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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. Prove that for positive integers n(1) and n(2), the value of express...

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  4. The value of abs(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+ i sqrt(3))/(1-isqrt(3)))+ ((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=0andA+B+C=180^(@) then the value of...

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  9. Find the sum 1xx(2-omega)xx(2-omega^(2))+2xx(-3-omega)xx(3-omega^(2))+...

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

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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))^(n2) is real iff

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  13. If |{:(6i,3i,1),(4,3i,-1),(20,3,i):}|=x+iy, then (x, y) is equal to

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  14. If cosalpha+2cosbeta+3cosgamma=sinalpha+2sinbeta+3singamma=0,t h e nt ...

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  15. If cosalpha+2cosbeta+3cosgamma=sinalpha+2sinbeta+3singamma=0,t h e nt ...

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

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

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

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

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  20. The vertices of a square are z(1),z(2),z(3) and z(4) taken in the anti...

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  21. Let lambda in R . If the origin and the non-real roots of 2z^2+2z+lam...

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