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If alpha and beta are non-real, then con...

If `alpha and beta` are non-real, then condition for `x^(2) + alpha x + beta = 0` to have real roots, is

A

`(alpha-bar(alpha))(beta-bar(beta))=(alpha bar(beta)-bar(alpha)beta)^(2)`

B

`(bar(alpha)-alpha)(alphabar(beta)-bar(alpha)beta)=(beta-bar(beta))^(2)`

C

`(beta-bar(beta))(alpha bar(beta)-bar(alpha)beta)=(bar(alpha)-alpha)^(2)`

D

none of these

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The correct Answer is:
To determine the condition for the quadratic equation \( x^2 + \alpha x + \beta = 0 \) to have real roots, given that \( \alpha \) and \( \beta \) are non-real, we can follow these steps: ### Step 1: Understand the Quadratic Equation The standard form of a quadratic equation is \( ax^2 + bx + c = 0 \). In our case, \( a = 1 \), \( b = \alpha \), and \( c = \beta \). ### Step 2: Use the Discriminant For a quadratic equation to have real roots, the discriminant must be non-negative. The discriminant \( D \) is given by: \[ D = b^2 - 4ac \] Substituting our values: \[ D = \alpha^2 - 4 \cdot 1 \cdot \beta = \alpha^2 - 4\beta \] ### Step 3: Set the Discriminant Condition Since we want the roots to be real, we need: \[ D \geq 0 \implies \alpha^2 - 4\beta \geq 0 \] ### Step 4: Analyze the Condition Given that \( \alpha \) and \( \beta \) are non-real, we can express them in terms of their real and imaginary parts. Let: \[ \alpha = a + bi \quad \text{and} \quad \beta = c + di \] where \( a, b, c, d \) are real numbers and \( b \neq 0 \), \( d \neq 0 \). ### Step 5: Substitute and Simplify Substituting \( \alpha \) into the discriminant condition: \[ (a + bi)^2 - 4(c + di) \geq 0 \] Calculating \( (a + bi)^2 \): \[ (a + bi)^2 = a^2 - b^2 + 2abi \] Thus, the discriminant becomes: \[ (a^2 - b^2 + 2abi) - 4(c + di) = (a^2 - b^2 - 4c) + (2ab - 4d)i \] ### Step 6: Set Real and Imaginary Parts For the discriminant to be non-negative, the imaginary part must equal zero: \[ 2ab - 4d = 0 \quad \text{(1)} \] And the real part must be non-negative: \[ a^2 - b^2 - 4c \geq 0 \quad \text{(2)} \] ### Step 7: Conclusion Thus, the conditions for the quadratic equation \( x^2 + \alpha x + \beta = 0 \) to have real roots, given that \( \alpha \) and \( \beta \) are non-real, are: 1. \( 2ab - 4d = 0 \) 2. \( a^2 - b^2 - 4c \geq 0 \)

To determine the condition for the quadratic equation \( x^2 + \alpha x + \beta = 0 \) to have real roots, given that \( \alpha \) and \( \beta \) are non-real, we can follow these steps: ### Step 1: Understand the Quadratic Equation The standard form of a quadratic equation is \( ax^2 + bx + c = 0 \). In our case, \( a = 1 \), \( b = \alpha \), and \( c = \beta \). ### Step 2: Use the Discriminant For a quadratic equation to have real roots, the discriminant must be non-negative. The discriminant \( D \) is given by: \[ ...
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