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If alpha and beta are the roots of the q...

If `alpha and beta are the roots of the quadratic equation `x^(2) + px + q = 0`, then form the quadratic equation whose roots are `alpha + (1)/(beta), beta + (1)/(alpha)`

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To find the quadratic equation whose roots are \( \alpha + \frac{1}{\beta} \) and \( \beta + \frac{1}{\alpha} \), we start with the given quadratic equation: \[ x^2 + px + q = 0 \] where \( \alpha \) and \( \beta \) are the roots. From Vieta's formulas, we know: 1. The sum of the roots \( \alpha + \beta = -p \) 2. The product of the roots \( \alpha \beta = q \) ### Step 1: Find the new roots The new roots are given as: \[ r_1 = \alpha + \frac{1}{\beta} \] \[ r_2 = \beta + \frac{1}{\alpha} \] ### Step 2: Simplify the new roots We can rewrite \( r_1 \) and \( r_2 \): \[ r_1 = \alpha + \frac{1}{\beta} = \alpha + \frac{\alpha}{\alpha \beta} = \frac{\alpha^2 + 1}{\beta} \] \[ r_2 = \beta + \frac{1}{\alpha} = \beta + \frac{\beta}{\alpha \beta} = \frac{\beta^2 + 1}{\alpha} \] ### Step 3: Find the sum of the new roots Now, we calculate the sum of the new roots: \[ r_1 + r_2 = \left( \alpha + \frac{1}{\beta} \right) + \left( \beta + \frac{1}{\alpha} \right) = \alpha + \beta + \frac{1}{\beta} + \frac{1}{\alpha} \] Using \( \alpha + \beta = -p \) and \( \frac{1}{\beta} + \frac{1}{\alpha} = \frac{\alpha + \beta}{\alpha \beta} = \frac{-p}{q} \): \[ r_1 + r_2 = -p + \frac{-p}{q} = -p\left(1 + \frac{1}{q}\right) = -p \cdot \frac{q + 1}{q} \] ### Step 4: Find the product of the new roots Next, we calculate the product of the new roots: \[ r_1 \cdot r_2 = \left( \alpha + \frac{1}{\beta} \right) \left( \beta + \frac{1}{\alpha} \right) \] \[ = \alpha \beta + \alpha \cdot \frac{1}{\alpha} + \beta \cdot \frac{1}{\beta} + \frac{1}{\alpha \beta} \] \[ = \alpha \beta + 1 + 1 + \frac{1}{\alpha \beta} = q + 2 + \frac{1}{q} \] ### Step 5: Form the new quadratic equation The quadratic equation with roots \( r_1 \) and \( r_2 \) can be expressed as: \[ x^2 - (r_1 + r_2)x + (r_1 \cdot r_2) = 0 \] Substituting the values we found: \[ x^2 + p \cdot \frac{q + 1}{q} x - \left(q + 2 + \frac{1}{q}\right) = 0 \] ### Final Result Thus, the required quadratic equation is: \[ x^2 + \frac{p(q + 1)}{q} x - \left(q + 2 + \frac{1}{q}\right) = 0 \]
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