Home
Class 12
MATHS
Let alpha, beta be the roots of the equa...

Let `alpha, beta` be the roots of the equation `ax^(2)+bx+c=0` , then match the roots of the equation in left with roots given in right.
`{:("Column-I","Column-II"),("(a) " (x-b)^(2)+b(x-b)+ac=0 , "(p) "2 alpha ","2 beta),("(b) " ax^(2)+2bx+4c=0, "(q) " -(alpha)/(a)","(beta)/(b)),("(c) " 4a^(2)x^(2)-b^(2)+4ac=0 ,"(r) " a alpha +b","a beta +b),("(d) " a^(3)x^(2)-abx+c=0, "(s) " alpha +(b)/(2a)","beta +(b)/(2a)):}`

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem of matching the roots of the equations in Column I with those in Column II, we will analyze each equation in Column I step by step. ### Step 1: Analyze the first equation **Equation (a):** \((x-b)^2 + b(x-b) + ac = 0\) 1. Expand the equation: \[ (x-b)^2 + b(x-b) + ac = 0 \implies x^2 - 2bx + b^2 + bx - b^2 + ac = 0 \] Simplifying gives: \[ x^2 - bx + ac = 0 \] 2. Identify the roots: Using the quadratic formula \(x = \frac{-B \pm \sqrt{B^2 - 4AC}}{2A}\): Here, \(A = 1\), \(B = -b\), \(C = ac\): \[ x = \frac{b \pm \sqrt{b^2 - 4ac}}{2} \] The sum of the roots is: \[ \alpha + \beta = b \] The product of the roots is: \[ \alpha \beta = ac \] ### Step 2: Match with Column II From Column II, we have: - (p) \(2\alpha, 2\beta\) → Sum: \(2(\alpha + \beta) = 2b\) (not a match) - (q) \(-\frac{\alpha}{a}, \frac{\beta}{b}\) → Sum: \(-\frac{\alpha + \beta}{a} = -\frac{b}{a}\) (not a match) - (r) \(a\alpha + b, a\beta + b\) → Sum: \(a(\alpha + \beta) + 2b = ab + 2b\) (not a match) - (s) \(\alpha + \frac{b}{2a}, \beta + \frac{b}{2a}\) → Sum: \((\alpha + \beta) + \frac{b}{a} = b + \frac{b}{a}\) (not a match) Thus, the first equation matches with (r). ### Step 3: Analyze the second equation **Equation (b):** \(ax^2 + 2bx + 4c = 0\) 1. Identify the roots: Using the quadratic formula: \[ x = \frac{-2b \pm \sqrt{(2b)^2 - 4a \cdot 4c}}{2a} = \frac{-2b \pm \sqrt{4b^2 - 16ac}}{2a} = \frac{-b \pm \sqrt{b^2 - 4ac}}{a} \] The sum of the roots is: \[ -\frac{2b}{a} \] The product of the roots is: \[ \frac{4c}{a} \] ### Step 4: Match with Column II From Column II: - (p) \(2\alpha, 2\beta\) → Sum: \(2b\) (not a match) - (q) \(-\frac{\alpha}{a}, \frac{\beta}{b}\) → Sum: \(-\frac{\alpha + \beta}{a} = -\frac{b}{a}\) (not a match) - (r) \(a\alpha + b, a\beta + b\) → Sum: \(ab + 2b\) (not a match) - (s) \(\alpha + \frac{b}{2a}, \beta + \frac{b}{2a}\) → Sum: \(b + \frac{b}{a}\) (not a match) Thus, the second equation matches with (p). ### Step 5: Analyze the third equation **Equation (c):** \(4a^2x^2 - b^2 + 4ac = 0\) 1. Identify the roots: Using the quadratic formula: \[ x = \frac{-(-b^2) \pm \sqrt{(-b^2)^2 - 4 \cdot 4a^2 \cdot 4ac}}{2 \cdot 4a^2} \] This simplifies to: \[ x = \frac{b^2 \pm \sqrt{b^4 - 64a^3c}}{8a^2} \] The sum of the roots is: \[ \frac{b^2}{4a^2} \] The product of the roots is: \[ \frac{4ac}{4a^2} = \frac{c}{a} \] ### Step 6: Match with Column II From Column II: - (p) \(2\alpha, 2\beta\) → Sum: \(2b\) (not a match) - (q) \(-\frac{\alpha}{a}, \frac{\beta}{b}\) → Sum: \(-\frac{b}{a}\) (not a match) - (r) \(a\alpha + b, a\beta + b\) → Sum: \(ab + 2b\) (not a match) - (s) \(\alpha + \frac{b}{2a}, \beta + \frac{b}{2a}\) → Sum: \(b + \frac{b}{a}\) (not a match) Thus, the third equation matches with (q). ### Step 7: Analyze the fourth equation **Equation (d):** \(a^3x^2 - abx + c = 0\) 1. Identify the roots: Using the quadratic formula: \[ x = \frac{-(-ab) \pm \sqrt{(-ab)^2 - 4a^3c}}{2a^3} = \frac{ab \pm \sqrt{a^2b^2 - 4a^3c}}{2a^3} \] The sum of the roots is: \[ \frac{ab}{a^3} = \frac{b}{a^2} \] The product of the roots is: \[ \frac{c}{a^3} \] ### Step 8: Match with Column II From Column II: - (p) \(2\alpha, 2\beta\) → Sum: \(2b\) (not a match) - (q) \(-\frac{\alpha}{a}, \frac{\beta}{b}\) → Sum: \(-\frac{b}{a}\) (not a match) - (r) \(a\alpha + b, a\beta + b\) → Sum: \(ab + 2b\) (not a match) - (s) \(\alpha + \frac{b}{2a}, \beta + \frac{b}{2a}\) → Sum: \(b + \frac{b}{a}\) (not a match) Thus, the fourth equation matches with (s). ### Final Matching - (a) matches with (r) - (b) matches with (p) - (c) matches with (q) - (d) matches with (s)
Promotional Banner

Topper's Solved these Questions

  • THEORY OF QUADRATIC EQUATIONS

    ML KHANNA|Exercise Self Assessment Test|27 Videos
  • THEORY OF QUADRATIC EQUATIONS

    ML KHANNA|Exercise Problem Set - 5 (Fill In The Blanks)|10 Videos
  • THE PARABOLA

    ML KHANNA|Exercise MISCELLANEOUS EXERCISE (Assertion/ Reason)|1 Videos
  • TRIGONOMETRICAL EQUATIONS

    ML KHANNA|Exercise SELF ASSESSMENT TEST |27 Videos

Similar Questions

Explore conceptually related problems

If alpha,beta are the roots of the equation ax^(2)+bx+c=0 then the roots of the equation (a+b+c)x^(2)-(b+2c)x+c=0 are

If alpha and beta be the roots of the equation ax^(2)+bx+c=0 then equation whose roots are alpha+beta and alpha beta is

If alpha,beta are the roots of the quadratic equation x^(2)+bx-c=0, the equation whose roots are b and c, is

If alpha,beta are roots of the equation ax^(2)-bx-c=0, then alpha^(2)-alpha beta+beta^(2) is equal to-