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The roots alpha and beta of the quadrati...

The roots `alpha and beta` of the quadratic equation `px^(2) + qx + r = 0` are real and of opposite signs. The roots of `alpha(x-beta)^(2) + beta(x-alpha)^(2) = 0` are:

A

positive

B

negative

C

ral and of opposite sign

D

imaginary

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To solve the problem, we need to analyze the given quadratic equation and derive the roots of the new equation step by step. ### Step 1: Understand the given equation We have the quadratic equation: \[ px^2 + qx + r = 0 \] with roots \( \alpha \) and \( \beta \) that are real and of opposite signs. ### Step 2: Write the new equation The new equation we need to solve is: \[ \alpha(x - \beta)^2 + \beta(x - \alpha)^2 = 0 \] ### Step 3: Expand the equation Let's expand the equation: 1. Expand \( (x - \beta)^2 \): \[ (x - \beta)^2 = x^2 - 2\beta x + \beta^2 \] 2. Expand \( (x - \alpha)^2 \): \[ (x - \alpha)^2 = x^2 - 2\alpha x + \alpha^2 \] Now substituting these expansions into the equation: \[ \alpha(x^2 - 2\beta x + \beta^2) + \beta(x^2 - 2\alpha x + \alpha^2) = 0 \] This simplifies to: \[ \alpha x^2 - 2\alpha \beta x + \alpha \beta^2 + \beta x^2 - 2\beta \alpha x + \beta \alpha^2 = 0 \] ### Step 4: Combine like terms Combine the terms: \[ (\alpha + \beta)x^2 - 2(\alpha + \beta) x + (\alpha \beta^2 + \beta \alpha^2) = 0 \] This can be rewritten as: \[ (\alpha + \beta)x^2 - 2(\alpha + \beta)x + \alpha \beta(\alpha + \beta) = 0 \] ### Step 5: Factor out common terms Factoring out \( (\alpha + \beta) \): \[ (\alpha + \beta)(x^2 - 2x + \alpha \beta) = 0 \] ### Step 6: Solve for roots The roots of the equation are found by setting each factor to zero: 1. \( \alpha + \beta = 0 \) (which is not possible since \( \alpha \) and \( \beta \) are of opposite signs) 2. Solve \( x^2 - 2x + \alpha \beta = 0 \) Using the quadratic formula: \[ x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} \] Here, \( a = 1, b = -2, c = \alpha \beta \): \[ x = \frac{2 \pm \sqrt{(-2)^2 - 4 \cdot 1 \cdot \alpha \beta}}{2 \cdot 1} \] \[ x = \frac{2 \pm \sqrt{4 - 4\alpha \beta}}{2} \] \[ x = 1 \pm \sqrt{1 - \alpha \beta} \] ### Step 7: Analyze the roots Since \( \alpha \) and \( \beta \) are of opposite signs, their product \( \alpha \beta < 0 \). Thus, \( 1 - \alpha \beta > 1 \), which means the square root is real and positive. ### Conclusion The roots of the equation \( \alpha(x - \beta)^2 + \beta(x - \alpha)^2 = 0 \) are: \[ x = 1 + \sqrt{1 - \alpha \beta} \quad \text{and} \quad x = 1 - \sqrt{1 - \alpha \beta} \]
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VIKAS GUPTA (BLACK BOOK) ENGLISH-QUADRATIC EQUATIONS -EXERCISE (SUBJECTIVE TYPE PROBLEMS)
  1. The roots alpha and beta of the quadratic equation px^(2) + qx + r = 0...

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  2. Let f (x) =ax ^(2) + bx+ c where a,b,c are integers. If sin ""pi/7. si...

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  3. Let a, b, c, d be distinct integers such that the equation (x - a) (x ...

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  4. Consider the equation (x^2 + x + 1)^2-(m-3)(x^2 + x + 1) +m=0--(1), w...

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  5. The number of positive integral values of , m le 16 for which the equa...

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  6. If the equation (m^(2) -12 )x^(4) -8x ^(2)-4=0 has no real roots, then...

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  7. The least positive integral value of 'x' satisfying (e^x-2)(sin(x+pi/...

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  8. The integral values of x for which x ^(2) + 17 x +7 is perfect square ...

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

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

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

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

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

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

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

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

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

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

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

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

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

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