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The roots of the quadratic equation x^(2...

The roots of the quadratic equation `x^(2)+px+8=0` are `alpha ` and `beta`. Obtain the values of p, if
(i) `alpha=beta^(2)`
(ii) `alpha-beta=2`.

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The correct Answer is:
To solve the problem step by step, we will address each condition separately. ### Given: The quadratic equation is \( x^2 + px + 8 = 0 \) with roots \( \alpha \) and \( \beta \). ### Step 1: Use Vieta's Formulas From Vieta's formulas, we know: - The sum of the roots \( \alpha + \beta = -p \) - The product of the roots \( \alpha \beta = 8 \) ### Step 2: Solve for \( p \) when \( \alpha = \beta^2 \) 1. Substitute \( \alpha = \beta^2 \) into the product of the roots: \[ \beta^2 \cdot \beta = 8 \implies \beta^3 = 8 \] Thus, solving for \( \beta \): \[ \beta = 2 \] 2. Now substitute \( \beta \) back to find \( \alpha \): \[ \alpha = \beta^2 = 2^2 = 4 \] 3. Now, use the sum of the roots to find \( p \): \[ \alpha + \beta = 4 + 2 = 6 \implies -p = 6 \implies p = -6 \] ### Step 3: Solve for \( p \) when \( \alpha - \beta = 2 \) 1. From the condition \( \alpha - \beta = 2 \), we can express \( \alpha \) in terms of \( \beta \): \[ \alpha = \beta + 2 \] 2. Substitute this into the product of the roots: \[ (\beta + 2) \beta = 8 \implies \beta^2 + 2\beta - 8 = 0 \] 3. Solve the quadratic equation using the quadratic formula: \[ \beta = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} = \frac{-2 \pm \sqrt{2^2 - 4 \cdot 1 \cdot (-8)}}{2 \cdot 1} = \frac{-2 \pm \sqrt{4 + 32}}{2} = \frac{-2 \pm \sqrt{36}}{2} \] \[ = \frac{-2 \pm 6}{2} \] Thus, the solutions for \( \beta \) are: \[ \beta = 2 \quad \text{or} \quad \beta = -4 \] 4. For \( \beta = 2 \): \[ \alpha = 2 + 2 = 4 \] 5. For \( \beta = -4 \): \[ \alpha = -4 + 2 = -2 \] 6. Now calculate \( p \) for both cases: - For \( \beta = 2 \) and \( \alpha = 4 \): \[ \alpha + \beta = 4 + 2 = 6 \implies -p = 6 \implies p = -6 \] - For \( \beta = -4 \) and \( \alpha = -2 \): \[ \alpha + \beta = -2 - 4 = -6 \implies -p = -6 \implies p = 6 \] ### Final Values of \( p \): Thus, the values of \( p \) are \( -6 \) and \( 6 \). ---
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