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If 0 gt a gt b gt c and the roots alpha...

If `0 gt a gt b gt c` and the roots `alpha, beta` are imaginary roots of `ax^(2) + bx + c = 0` then

A

`|alpha|= |beta|`

B

`|alpha| gt 1`

C

`|beta| lt 1`

D

`alpha+beta=0`

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem, we need to analyze the given quadratic equation \( ax^2 + bx + c = 0 \) under the condition that the roots \( \alpha \) and \( \beta \) are imaginary. ### Step-by-Step Solution: 1. **Understand the Condition for Imaginary Roots**: For the roots of the quadratic equation \( ax^2 + bx + c = 0 \) to be imaginary, the discriminant must be less than zero. The discriminant \( D \) is given by: \[ D = b^2 - 4ac \] Therefore, we need: \[ b^2 - 4ac < 0 \] 2. **Analyze the Given Inequalities**: We are given that \( 0 > a > b > c \). This means that \( a, b, c \) are all negative numbers. 3. **Substituting the Values**: Since \( a, b, c < 0 \), we can analyze the product \( ac \): - Since both \( a \) and \( c \) are negative, \( ac > 0 \) (the product of two negative numbers is positive). 4. **Evaluating the Discriminant**: Since \( b < 0 \) and \( a, c < 0 \), we can say: \[ b^2 > 0 \quad \text{and} \quad 4ac > 0 \] Therefore, \( b^2 - 4ac < 0 \) holds true, confirming that the roots are indeed imaginary. 5. **Expressing the Roots**: The roots can be expressed in the form: \[ \alpha = A + Bi \quad \text{and} \quad \beta = A - Bi \] where \( A \) is the real part and \( B \) is the imaginary part. 6. **Finding the Magnitudes**: The magnitude of \( \alpha \) is given by: \[ |\alpha| = \sqrt{A^2 + B^2} \] Similarly, the magnitude of \( \beta \) is: \[ |\beta| = \sqrt{A^2 + B^2} \] Since both magnitudes are equal, we have: \[ |\alpha| = |\beta| \] 7. **Conclusion**: From the analysis, we find that the magnitudes of the imaginary roots \( \alpha \) and \( \beta \) are equal. Therefore, the correct option is: \[ \text{Option A: } |\alpha| = |\beta| \]
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