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If alpha, beta, gamma are the roots of ...

If `alpha, beta, gamma` are the roots of the equation `x^3 + px^2 + qx + r = n` then the value of `(alpha - 1/(beta gamma)) (beta -1/(gamma alpha)) (gamma-1/(alpha beta))` is:

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To solve the problem, we need to find the value of the expression: \[ (\alpha - \frac{1}{\beta \gamma})(\beta - \frac{1}{\gamma \alpha})(\gamma - \frac{1}{\alpha \beta}) \] where \(\alpha, \beta, \gamma\) are the roots of the equation \(x^3 + px^2 + qx + r = n\). ### Step 1: Rewrite the equation We start with the equation: \[ x^3 + px^2 + qx + r - n = 0 \] This implies that the roots \(\alpha, \beta, \gamma\) satisfy the polynomial equation \(x^3 + px^2 + qx + (r - n) = 0\). ### Step 2: Use Vieta's Formulas From Vieta's formulas, we know: - \(\alpha + \beta + \gamma = -p\) - \(\alpha \beta + \beta \gamma + \gamma \alpha = q\) - \(\alpha \beta \gamma = -(r - n)\) ### Step 3: Simplify the expression Now we simplify the expression: \[ (\alpha - \frac{1}{\beta \gamma})(\beta - \frac{1}{\gamma \alpha})(\gamma - \frac{1}{\alpha \beta}) \] Substituting \(\beta \gamma = \frac{\alpha \beta \gamma}{\alpha}\), \(\gamma \alpha = \frac{\alpha \beta \gamma}{\beta}\), and \(\alpha \beta = \frac{\alpha \beta \gamma}{\gamma}\): \[ = \left(\alpha - \frac{1}{\frac{\alpha \beta \gamma}{\alpha}}\right)\left(\beta - \frac{1}{\frac{\alpha \beta \gamma}{\beta}}\right)\left(\gamma - \frac{1}{\frac{\alpha \beta \gamma}{\gamma}}\right) \] This simplifies to: \[ = \left(\alpha - \frac{\alpha}{\alpha \beta \gamma}\right)\left(\beta - \frac{\beta}{\alpha \beta \gamma}\right)\left(\gamma - \frac{\gamma}{\alpha \beta \gamma}\right) \] \[ = \left(\alpha \left(1 - \frac{1}{\beta \gamma}\right)\right)\left(\beta \left(1 - \frac{1}{\gamma \alpha}\right)\right)\left(\gamma \left(1 - \frac{1}{\alpha \beta}\right)\right) \] ### Step 4: Factor out common terms Now, factor out \(\alpha \beta \gamma\): \[ = \frac{(\alpha \beta \gamma)^3 - (\alpha + \beta + \gamma)}{\alpha \beta \gamma} \] ### Step 5: Substitute the values Substituting the values from Vieta's formulas: \[ = \frac{(-(r - n))^3 - (-p)}{-(r - n)} \] This simplifies to: \[ = \frac{(r - n)^3 + p}{r - n} \] ### Final Result Thus, the value of the expression is: \[ = (r - n)^2 + \frac{p}{r - n} \]
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