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

If ` alpha, beta, gamma ` be the roots of the equation ` x(1+x^(2))+x^(2)(6+x)+2=0` then match the entries of column-I with those of column-II.
`{:("column-I" , " Column -II"),("(A) " alpha^(-1)+beta^(-1)+gamma^(-1) " is equal to " , "(p) 8"),("(B)" alpha^(2)+beta^(2)+gamma^(2)" equals" , "(q)" -1/2),("(C)"(alpha^(-1)+beta^(-1)+gamma^(-1))-(alpha+beta+gamma) " is equal to " , "(r) -1"),("(D)"[alpha^(-1)+beta^(-1)+gamma^(-1)] " equals where [.] denotes the greatest integer equal to " , "(t)" 5/2):}`

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To solve the equation \( x(1+x^{2}) + x^{2}(6+x) + 2 = 0 \) and find the relationships between the roots \( \alpha, \beta, \gamma \), we will follow these steps: ### Step 1: Simplify the Equation Start with the given equation: \[ x(1+x^{2}) + x^{2}(6+x) + 2 = 0 \] Distributing the terms: \[ x + x^{3} + 6x^{2} + x^{3} + 2 = 0 \] Combining like terms: \[ 2x^{3} + 6x^{2} + x + 2 = 0 \] ### Step 2: Identify Coefficients This is a cubic equation of the form \( ax^3 + bx^2 + cx + d = 0 \) where: - \( a = 2 \) - \( b = 6 \) - \( c = 1 \) - \( d = 2 \) ### Step 3: Use Vieta's Formulas From Vieta's formulas, we can find: 1. The sum of the roots \( \alpha + \beta + \gamma = -\frac{b}{a} = -\frac{6}{2} = -3 \) 2. The sum of the products of the roots taken two at a time \( \alpha\beta + \beta\gamma + \gamma\alpha = \frac{c}{a} = \frac{1}{2} \) 3. The product of the roots \( \alpha\beta\gamma = -\frac{d}{a} = -\frac{2}{2} = -1 \) ### Step 4: Calculate \( \alpha^{-1} + \beta^{-1} + \gamma^{-1} \) Using the formula: \[ \alpha^{-1} + \beta^{-1} + \gamma^{-1} = \frac{\alpha\beta + \beta\gamma + \gamma\alpha}{\alpha\beta\gamma} \] Substituting the values: \[ \alpha^{-1} + \beta^{-1} + \gamma^{-1} = \frac{\frac{1}{2}}{-1} = -\frac{1}{2} \] Thus, \( \alpha^{-1} + \beta^{-1} + \gamma^{-1} = -\frac{1}{2} \) which corresponds to entry \( (q) \). ### Step 5: Calculate \( \alpha^2 + \beta^2 + \gamma^2 \) Using the identity: \[ \alpha^2 + \beta^2 + \gamma^2 = (\alpha + \beta + \gamma)^2 - 2(\alpha\beta + \beta\gamma + \gamma\alpha) \] Substituting the known values: \[ \alpha^2 + \beta^2 + \gamma^2 = (-3)^2 - 2 \times \frac{1}{2} = 9 - 1 = 8 \] Thus, \( \alpha^2 + \beta^2 + \gamma^2 = 8 \) which corresponds to entry \( (p) \). ### Step 6: Calculate \( \alpha^{-1} + \beta^{-1} + \gamma^{-1} - (\alpha + \beta + \gamma) \) We already found \( \alpha^{-1} + \beta^{-1} + \gamma^{-1} = -\frac{1}{2} \) and \( \alpha + \beta + \gamma = -3 \): \[ \alpha^{-1} + \beta^{-1} + \gamma^{-1} - (\alpha + \beta + \gamma) = -\frac{1}{2} - (-3) = -\frac{1}{2} + 3 = \frac{5}{2} \] Thus, this corresponds to entry \( (t) \). ### Step 7: Calculate the Greatest Integer of \( \alpha^{-1} + \beta^{-1} + \gamma^{-1} \) We already found \( \alpha^{-1} + \beta^{-1} + \gamma^{-1} = -\frac{1}{2} \). The greatest integer function \( \lfloor -\frac{1}{2} \rfloor = -1 \). Thus, this corresponds to entry \( (r) \). ### Summary of Results - \( (A) \) corresponds to \( (q) \) - \( (B) \) corresponds to \( (p) \) - \( (C) \) corresponds to \( (t) \) - \( (D) \) corresponds to \( (r) \)
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