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Let a,b,c in R and a ne 0. If alpha is a...

Let `a,b,c in R and a ne 0`. If `alpha` is a root `a^(2) x^(2) +bx+c=0, beta` is a root of `a^(2) x^(2)-bx-c=0 and 0 lt alpha lt beta`, then the equation `a^(2)x^(2)+2bx+2c=0` has a root `gamma` that always satisfies

A

`gamma = alpha`

B

`gamma = beta`

C

`gamma =(alpha +beta)//2`

D

`alpha lt gamma lt beta`

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The correct Answer is:
To solve the problem step-by-step, we will analyze the given quadratic equations and their roots. ### Step 1: Understand the Given Equations We have two quadratic equations: 1. \( a^2 x^2 + bx + c = 0 \) with root \( \alpha \) 2. \( a^2 x^2 - bx - c = 0 \) with root \( \beta \) ### Step 2: Write the Conditions for Roots Since \( \alpha \) is a root of the first equation, we can write: \[ a^2 \alpha^2 + b \alpha + c = 0 \tag{1} \] Similarly, since \( \beta \) is a root of the second equation, we can write: \[ a^2 \beta^2 - b \beta - c = 0 \tag{2} \] ### Step 3: Analyze the New Equation We need to analyze the equation: \[ a^2 x^2 + 2bx + 2c = 0 \] We will denote this function as \( f(x) = a^2 x^2 + 2bx + 2c \). ### Step 4: Evaluate \( f(\alpha) \) Substituting \( \alpha \) into \( f(x) \): \[ f(\alpha) = a^2 \alpha^2 + 2b \alpha + 2c \] From equation (1), we know that: \[ a^2 \alpha^2 + b \alpha + c = 0 \] Thus, we can express \( f(\alpha) \) as: \[ f(\alpha) = (a^2 \alpha^2 + b \alpha + c) + b \alpha + c = 0 + b \alpha + c = b \alpha + c \] ### Step 5: Evaluate \( f(\beta) \) Now substituting \( \beta \) into \( f(x) \): \[ f(\beta) = a^2 \beta^2 + 2b \beta + 2c \] From equation (2), we have: \[ a^2 \beta^2 - b \beta - c = 0 \] Thus, we can express \( f(\beta) \) as: \[ f(\beta) = (a^2 \beta^2 - b \beta - c) + 3b \beta + 3c = 0 + 3b \beta + 3c = 3b \beta + 3c \] ### Step 6: Analyze the Product \( f(\alpha) \cdot f(\beta) \) Now, we can analyze the product: \[ f(\alpha) \cdot f(\beta) = (b \alpha + c)(3b \beta + 3c) \] This product will help us determine the nature of the roots of the equation \( a^2 x^2 + 2bx + 2c = 0 \). ### Step 7: Determine the Nature of the Root \( \gamma \) Since \( 0 < \alpha < \beta \), we can conclude that: 1. \( f(\alpha) < 0 \) (as \( \alpha \) is less than the root) 2. \( f(\beta) > 0 \) (as \( \beta \) is greater than the root) Thus, by the Intermediate Value Theorem, there exists a root \( \gamma \) such that: \[ \alpha < \gamma < \beta \] ### Conclusion The root \( \gamma \) of the equation \( a^2 x^2 + 2bx + 2c = 0 \) always satisfies: \[ \alpha < \gamma < \beta \]
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