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The sum of the roots of the equation `x^(2)+bx+c=0` (wheere b and c are non-zero) is equal to the sum of the reciprocals of their squares. Then `(1)/(c),b,(c)/(b)` are in

A

AP

B

GP

C

HP

D

None of the above

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The correct Answer is:
To solve the problem, we start with the quadratic equation given: \[ x^2 + bx + c = 0 \] Let the roots of the equation be \( \alpha \) and \( \beta \). According to Vieta's formulas, we know: 1. The sum of the roots \( \alpha + \beta = -b \) 2. The product of the roots \( \alpha \beta = c \) We are given that the sum of the roots is equal to the sum of the reciprocals of their squares: \[ \alpha + \beta = \frac{1}{\alpha^2} + \frac{1}{\beta^2} \] We can rewrite the right-hand side using the identity for the sum of squares: \[ \frac{1}{\alpha^2} + \frac{1}{\beta^2} = \frac{\beta^2 + \alpha^2}{\alpha^2 \beta^2} \] Using the identity \( \alpha^2 + \beta^2 = (\alpha + \beta)^2 - 2\alpha\beta \), we substitute: \[ \alpha^2 + \beta^2 = (-b)^2 - 2c = b^2 - 2c \] Thus, we have: \[ \frac{1}{\alpha^2} + \frac{1}{\beta^2} = \frac{b^2 - 2c}{c^2} \] Now, equating the two expressions for the sum of the roots: \[ -b = \frac{b^2 - 2c}{c^2} \] Cross-multiplying gives: \[ -bc^2 = b^2 - 2c \] Rearranging this equation leads to: \[ b^2 + bc^2 - 2c = 0 \] This is a quadratic equation in terms of \( b \). We can apply the quadratic formula: \[ b = \frac{-c^2 \pm \sqrt{(c^2)^2 + 8c}}{2} \] Next, we need to analyze the relationship between \( \frac{1}{c}, b, \frac{c}{b} \). 1. From the quadratic equation, we can find the discriminant to ensure \( b \) has real values. 2. We will check if \( \frac{1}{c}, b, \frac{c}{b} \) are in arithmetic progression (AP), geometric progression (GP), or harmonic progression (HP). To check if \( \frac{1}{c}, b, \frac{c}{b} \) are in GP, we need to verify: \[ b^2 = \frac{1}{c} \cdot \frac{c}{b} \] This simplifies to: \[ b^2 = \frac{1}{b} \] Thus, multiplying both sides by \( b \) (assuming \( b \neq 0 \)) gives: \[ b^3 = 1 \implies b = 1 \] Now substituting \( b = 1 \) back into the original quadratic equation gives us the relationships needed to check the progressions. ### Conclusion: The values \( \frac{1}{c}, b, \frac{c}{b} \) are in geometric progression (GP) if \( b^3 = 1 \).

To solve the problem, we start with the quadratic equation given: \[ x^2 + bx + c = 0 \] Let the roots of the equation be \( \alpha \) and \( \beta \). According to Vieta's formulas, we know: 1. The sum of the roots \( \alpha + \beta = -b \) 2. The product of the roots \( \alpha \beta = c \) ...
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