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The sum of all intergral values of lamda...

The sum of all intergral values of `lamda` for which `(lamda^(2) + lamda -2) x ^(2) + (lamda +2) x lt 1 AA x in R,` is:

A

`-1`

B

`-3`

C

0

D

`-2`

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The correct Answer is:
To solve the problem, we need to find the sum of all integral values of \( \lambda \) for which the inequality \[ (\lambda^2 + \lambda - 2)x^2 + (\lambda + 2)x < 1 \] holds for all real numbers \( x \). ### Step 1: Rearranging the Inequality We start by rearranging the inequality: \[ (\lambda^2 + \lambda - 2)x^2 + (\lambda + 2)x - 1 < 0 \] This is a quadratic inequality in \( x \). ### Step 2: Identifying Coefficients Let \( a = \lambda^2 + \lambda - 2 \), \( b = \lambda + 2 \), and \( c = -1 \). The quadratic can be expressed as: \[ ax^2 + bx + c < 0 \] ### Step 3: Conditions for the Quadratic to be Negative For the quadratic \( ax^2 + bx + c < 0 \) to hold for all \( x \), the following conditions must be satisfied: 1. \( a < 0 \) (the parabola opens downwards). 2. The discriminant \( D = b^2 - 4ac < 0 \) (there are no real roots). ### Step 4: Finding Conditions on \( a \) We need to solve \( a < 0 \): \[ \lambda^2 + \lambda - 2 < 0 \] Factoring the quadratic: \[ (\lambda - 1)(\lambda + 2) < 0 \] ### Step 5: Solving the Inequality The critical points are \( \lambda = -2 \) and \( \lambda = 1 \). We test intervals determined by these points: - For \( \lambda < -2 \): Choose \( \lambda = -3 \) → \( (-3 - 1)(-3 + 2) = (-4)(-1) > 0 \) - For \( -2 < \lambda < 1 \): Choose \( \lambda = 0 \) → \( (0 - 1)(0 + 2) = (-1)(2) < 0 \) - For \( \lambda > 1 \): Choose \( \lambda = 2 \) → \( (2 - 1)(2 + 2) = (1)(4) > 0 \) Thus, the solution to \( (\lambda - 1)(\lambda + 2) < 0 \) is: \[ -2 < \lambda < 1 \] ### Step 6: Finding Integral Values of \( \lambda \) The integral values of \( \lambda \) in the interval \( (-2, 1) \) are \( -1 \) and \( 0 \). ### Step 7: Summing Integral Values Now, we sum the integral values: \[ -1 + 0 = -1 \] ### Final Answer The sum of all integral values of \( \lambda \) for which the inequality holds is: \[ \boxed{-1} \]
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VIKAS GUPTA (BLACK BOOK) ENGLISH-QUADRATIC EQUATIONS -EXERCISE (SUBJECTIVE TYPE PROBLEMS)
  1. The sum of all intergral values of lamda for which (lamda^(2) + lamda ...

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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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