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Let p, q, r in R and r gt p gt 0. If the...

Let p, q, r `in` R and `r gt p gt 0`. If the quadratic equation `px^(2) + qx + r = 0` has two complex roots `alpha and beta`, then `|alpha|+|beta|`, is

A

less than 2 but not equat to 1

B

equal to 2

C

equal to 1

D

greater than 2

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The correct Answer is:
To solve the problem, we need to analyze the given quadratic equation and the conditions provided. ### Step-by-Step Solution: 1. **Identify the Quadratic Equation**: The quadratic equation given is \( px^2 + qx + r = 0 \). 2. **Conditions on Roots**: We know that the roots \( \alpha \) and \( \beta \) are complex. For a quadratic equation to have complex roots, the discriminant must be negative: \[ D = q^2 - 4pr < 0 \] 3. **Roots in Conjugate Pairs**: Since the roots are complex, they can be expressed as \( \alpha = a + bi \) and \( \beta = a - bi \), where \( a \) and \( b \) are real numbers, and \( b \neq 0 \). This means that \( |\alpha| = |\beta| \). 4. **Product of Roots**: The product of the roots of the quadratic equation is given by: \[ \alpha \beta = \frac{r}{p} \] Since \( r > p > 0 \), we have: \[ \frac{r}{p} > 1 \implies |\alpha| \cdot |\beta| > 1 \] 5. **Magnitude of Roots**: Because \( |\alpha| = |\beta| \), we can let \( |\alpha| = |\beta| = k \). Therefore: \[ k^2 = |\alpha| \cdot |\beta| > 1 \implies k > 1 \] 6. **Sum of Magnitudes**: Now, we can find the sum of the magnitudes: \[ |\alpha| + |\beta| = k + k = 2k \] Since \( k > 1 \), it follows that: \[ 2k > 2 \] 7. **Conclusion**: Therefore, we conclude that: \[ |\alpha| + |\beta| > 2 \] ### Final Answer: The value of \( |\alpha| + |\beta| \) is greater than 2. ---

To solve the problem, we need to analyze the given quadratic equation and the conditions provided. ### Step-by-Step Solution: 1. **Identify the Quadratic Equation**: The quadratic equation given is \( px^2 + qx + r = 0 \). 2. **Conditions on Roots**: ...
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OBJECTIVE RD SHARMA-QUADRATIC EXPRESSIONS AND EQUATIONS -Chapter Test
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  2. The set of values of a for which x^2+ax+sin^(-1)(x^2-4x+5)+cos^(-1)(x^...

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  3. The set of possible values of lambda for which x^2-(lambda^2-5 lambda...

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  4. The equation (a + 2)x^2 + (a-3)x = 2a - 1, a != -2 has roots rational ...

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  5. If sinalpha,sinbeta and cosalpha are in G.P then roots of x^2+2xcotbet...

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  6. If alpha,beta are roots of x^2-3x+a=0,a in Ra n dalpha<1<beta, then f...

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  7. If the equations ax^2+bx+c=0 and cx^2+bx+a=0, a!=c have a negative com...

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  8. If the roots of the equation x^3-12x^2 +39x -28 =0 are in AP, then the...

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  9. If the roots of a1x^2 + b1x+ c1 = 0 are alpha1 ,beta 1 and those o...

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  10. If the roots of the equation ax^(2) - 4x + a^(2) = 0 are imaginary and...

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  11. If a,b,c are positive real numbers, then the number of positive real r...

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  12. If the absolute value of the difference of the roots of the equation x...

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  13. If alpha, beta are roots of the equation 375 x^(2) - 25x - 2 = 0 and S...

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  14. The quadratic equation x^(2) + (a^(2) - 2) x - 2a^(2) and x^(2) - 3x +...

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  15. If the roots of the equation ax^2 + bx + c = 0, a != 0 (a, b, c are re...

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  16. The value of m for which the equation x^3-mx^2+3x-2=0 has two roots ...

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  17. The equation formed by decreasing each root of the equation a x^2 + b...

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  18. If the roots of the equation ax^2-bx-c=0 are changed by same quantity ...

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  19. If x^2-2rprx+r=0; r=1, 2,3 are three quadratic equations of which each...

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  20. If x^2+px+1 is a factor of ax^3+bx+c then a) a^2+c^2=-ab b) a^2+c^2a...

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  21. If (x-1)^3 is a factor of x^4+ax^3+bx^2+cx-1=0 then the other factor ...

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