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Let p(x) =x^6-x^5-x^3-x^2-x and alpha, b...

Let `p(x) =x^6-x^5-x^3-x^2-x` and `alpha, beta, gamma, delta` are the roots of the equation `x^4-x^3-x^2-1=0` then `P(alpha)+P(beta)+P(gamma)+P(delta)=`

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To solve the problem, we need to evaluate \( P(\alpha) + P(\beta) + P(\gamma) + P(\delta) \) where \( P(x) = x^6 - x^5 - x^3 - x^2 - x \) and \( \alpha, \beta, \gamma, \delta \) are the roots of the equation \( x^4 - x^3 - x^2 - 1 = 0 \). ### Step 1: Express \( P(x) \) We start with the polynomial: \[ P(x) = x^6 - x^5 - x^3 - x^2 - x \] ### Step 2: Substitute the roots into \( P(x) \) We will evaluate \( P(\alpha) \): \[ P(\alpha) = \alpha^6 - \alpha^5 - \alpha^3 - \alpha^2 - \alpha \] ### Step 3: Use the polynomial equation Since \( \alpha \) is a root of \( x^4 - x^3 - x^2 - 1 = 0 \), we can express higher powers of \( \alpha \) in terms of lower powers: \[ \alpha^4 = \alpha^3 + \alpha^2 + 1 \] Now we can find \( \alpha^5 \) and \( \alpha^6 \): \[ \alpha^5 = \alpha \cdot \alpha^4 = \alpha(\alpha^3 + \alpha^2 + 1) = \alpha^4 + \alpha^3 + \alpha = (\alpha^3 + \alpha^2 + 1) + \alpha^3 + \alpha = 2\alpha^3 + \alpha^2 + \alpha + 1 \] \[ \alpha^6 = \alpha \cdot \alpha^5 = \alpha(2\alpha^3 + \alpha^2 + \alpha + 1) = 2\alpha^4 + \alpha^3 + \alpha^2 + \alpha = 2(\alpha^3 + \alpha^2 + 1) + \alpha^3 + \alpha^2 + \alpha \] \[ = 3\alpha^3 + 3\alpha^2 + 2 + \alpha \] ### Step 4: Substitute \( \alpha^5 \) and \( \alpha^6 \) back into \( P(\alpha) \) Now substituting these back into \( P(\alpha) \): \[ P(\alpha) = (3\alpha^3 + 3\alpha^2 + 2 + \alpha) - (2\alpha^3 + \alpha^2 + \alpha + 1) - \alpha^3 - \alpha^2 - \alpha \] Simplifying this: \[ = 3\alpha^3 + 3\alpha^2 + 2 + \alpha - 2\alpha^3 - \alpha^2 - \alpha - 1 - \alpha^3 - \alpha^2 - \alpha \] \[ = (3\alpha^3 - 2\alpha^3 - \alpha^3) + (3\alpha^2 - \alpha^2 - \alpha^2) + (2 - 1) + (\alpha - \alpha - \alpha) \] \[ = 0\alpha^3 + 1\alpha^2 + 1 + 0\alpha = \alpha^2 + 1 \] ### Step 5: Calculate \( P(\alpha) + P(\beta) + P(\gamma) + P(\delta) \) Now we can sum up \( P(\alpha) + P(\beta) + P(\gamma) + P(\delta) \): \[ P(\alpha) + P(\beta) + P(\gamma) + P(\delta) = (\alpha^2 + 1) + (\beta^2 + 1) + (\gamma^2 + 1) + (\delta^2 + 1) \] \[ = (\alpha^2 + \beta^2 + \gamma^2 + \delta^2) + 4 \] ### Step 6: Use the identity for the sum of squares Using the identity: \[ \alpha^2 + \beta^2 + \gamma^2 + \delta^2 = (\alpha + \beta + \gamma + \delta)^2 - 2(\alpha\beta + \alpha\gamma + \alpha\delta + \beta\gamma + \beta\delta + \gamma\delta) \] From the polynomial \( x^4 - x^3 - x^2 - 1 = 0 \): - The sum of the roots \( \alpha + \beta + \gamma + \delta = 1 \) - The sum of the products of the roots taken two at a time \( \alpha\beta + \alpha\gamma + \alpha\delta + \beta\gamma + \beta\delta + \gamma\delta = -1 \) Thus: \[ \alpha^2 + \beta^2 + \gamma^2 + \delta^2 = 1^2 - 2(-1) = 1 + 2 = 3 \] ### Final Calculation Now substituting back: \[ P(\alpha) + P(\beta) + P(\gamma) + P(\delta) = 3 + 4 = 7 \] ### Conclusion The final answer is: \[ \boxed{7} \]
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VIKAS GUPTA (BLACK BOOK) ENGLISH-QUADRATIC EQUATIONS -EXERCISE (SUBJECTIVE TYPE PROBLEMS)
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  2. The integral values of x for which x ^(2) + 17 x +7 is perfect square ...

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  3. Let p(x) =x^6-x^5-x^3-x^2-x and alpha, beta, gamma, delta are the root...

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  4. The number of real values of 'a' for which the largest value of the fu...

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  5. The number of all values of n, (whre n is a whole number ) for which t...

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  6. The number of negative intergral values of m for which the expression ...

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  7. If the expression a x^4+b x^3-x^2+2x+3 has remainder 4x+3 when divided...

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  8. The smallest value of k for which both roots of the equation x^(2)-8kx...

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  9. If x ^(2) -3x+2 is a factor of x ^(4) -px ^(2) +q=0, then p+q=

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  10. The expression x^2 + 2xy + ky^2 + 2x + k = 0 can be resolved into two ...

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  11. The curve y=(lambda=1)x^2+2 intersects the curve y=lambdax+3 in exactl...

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  12. Find the number of integral vaues of 'a' for which the range of functi...

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  13. When x ^(100) is divided by x ^(2) -3x +2, the remainder is (2 ^(k +1)...

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  14. Let p(x)=0 be a polynomial equation of the least possible degree, with...

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  15. The range of value's of k for which the equation 2 cos^(4) x - sin^(4...

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  16. Let p (x) be a polynomial with real coefficient and p (x)=x^(2)+2x+1. ...

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  17. Find the smallest positive integral values of a for which the greater ...

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  18. If the equation x ^(4)+kx ^(2) +k=0 has exactly two distinct real root...

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  19. Let P (x)=x ^(6) -x ^(5) -x ^(3) -x ^(2) -x and alpha, beta, gamma, de...

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  20. The number of integral value of a,a, in [-5, 5] for which the equation...

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