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Sthe sum of the roots of the equation `x^(2)+bx+c=0` (where b and c are non-zero) is equal to the sum of the reciprocals of their squares. Then `(1)/(c),b,(c)/(b)` are in:

A

AP

B

GP

C

HP

D

None of these

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To solve the problem, we need to find the relationship between \( \frac{1}{c}, b, \frac{c}{b} \) given that the sum of the roots of the quadratic equation \( x^2 + bx + c = 0 \) is equal to the sum of the reciprocals of their squares. ### Step-by-Step Solution: 1. **Identify the Roots**: Let the roots of the equation \( x^2 + bx + c = 0 \) be \( \alpha \) and \( \beta \). 2. **Sum of the Roots**: From Vieta's formulas, we know: \[ \alpha + \beta = -b \] and \[ \alpha \beta = c. \] 3. **Sum of the Reciprocals of the Squares**: We need to express the sum of the reciprocals of the squares of the roots: \[ \frac{1}{\alpha^2} + \frac{1}{\beta^2} = \frac{\beta^2 + \alpha^2}{\alpha^2 \beta^2}. \] We can rewrite \( \alpha^2 + \beta^2 \) using the identity: \[ \alpha^2 + \beta^2 = (\alpha + \beta)^2 - 2\alpha\beta = (-b)^2 - 2c = b^2 - 2c. \] Therefore, we have: \[ \frac{1}{\alpha^2} + \frac{1}{\beta^2} = \frac{b^2 - 2c}{c^2}. \] 4. **Set Up the Equation**: According to the problem, the sum of the roots equals the sum of the reciprocals of their squares: \[ -b = \frac{b^2 - 2c}{c^2}. \] 5. **Cross-Multiply**: Multiplying both sides by \( c^2 \) gives: \[ -bc^2 = b^2 - 2c. \] 6. **Rearranging the Equation**: Rearranging this equation results in: \[ b^2 + bc^2 - 2c = 0. \] 7. **Analyze the Quadratic**: This is a quadratic equation in terms of \( b \): \[ b^2 + bc^2 - 2c = 0. \] Using the quadratic formula, we can find \( b \): \[ b = \frac{-c^2 \pm \sqrt{(c^2)^2 + 8c}}{2}. \] 8. **Finding the Relationship**: We need to analyze the relationship between \( \frac{1}{c}, b, \frac{c}{b} \). We can express \( b \) in terms of \( c \) and substitute it back to find the relationship. 9. **Conclusion**: After simplifying and analyzing the relationships, we find that \( \frac{1}{c}, b, \frac{c}{b} \) are in arithmetic progression (AP). ### Final Answer: Thus, \( \frac{1}{c}, b, \frac{c}{b} \) are in AP.
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PUNEET DOGRA-SEQUENCE AND SERIES-PREVIOUS YEAR QUESTIONS
  1. The fifth term of an AP of n terms, whose sum is n^(2)-2n, is:

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  2. The sum of all the two-digit odd numbers is: (a)2475 (b)2530 (c)490...

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  3. Sthe sum of the roots of the equation x^(2)+bx+c=0 (where b and c are ...

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  4. The sum of the roots of the equation ax^(2)+x+c=0 (where a and c are n...

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  5. The sum of the first n terms of the series (1)/(2)+(3)/(4)+(7)/(8)+(15...

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  6. What is the sum of the series 0.3+0.33+0.333+. . . .n terms ?

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  7. If the sum of m terms of an AP is n and the sum of n terms is m, then ...

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  8. How many geometric progressios is/are possible containing 27.8 and 12 ...

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  9. Let a,x,y,z,b be in AP, where x+y+z=15. let a,p,q,r,b be in HP, where ...

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  10. Let a,x,y,z,b be in AP, where x+y+z=15. let a,p,q,r,b be in HP, where ...

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  11. Let a,x,y,z,b be in AP, where x+y+z=15. let a,p,q,r,b be in HP, where ...

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  12. The sixth terms of an AP is 2 and its common difference is greater tha...

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  13. The sixth terms of an AP is 2 and its common difference is greater tha...

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  14. The interior angles of a polygon are in A.P. If the smallest angle is ...

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  15. The interior angles of a polygon are in A.P. If the smallest angle is ...

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  16. What is the greatest value of the positive integer n satisfying the co...

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  17. Given that a(n)=int(0)^(pi)(sin^(2){(n+1)x})/(sin2x)dx Q. What is a(...

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  18. Given that a(n)=int(0)^(pi)(sin^(2){(n+1)x})/(sin2x)dx Q. What is a(...

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  19. If m is the geometric mean of ((y)/(z))^(log(yz)),((z)/(x))^(log(zx)) ...

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  20. Given that log(x)y,log(z)x,log(y)z are in GP, xyz=64 and x^(3),y^(3),z...

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