Home
Class 12
MATHS
If alpha, beta be the roots x^(2)-px+q=0...

If `alpha, beta` be the roots `x^(2)-px+q=0 and alpha', beta'` be those of `x^(2)-p'x+q'=0`, then the value of
`(alpha-alpha')^(2) +(beta-alpha')^(2) +(alpha-beta')^(2)+(beta-beta')^(2)=`…..

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem, we need to calculate the expression: \[ (\alpha - \alpha')^2 + (\beta - \alpha')^2 + (\alpha - \beta')^2 + (\beta - \beta')^2 \] where \(\alpha, \beta\) are the roots of the equation \(x^2 - px + q = 0\) and \(\alpha', \beta'\) are the roots of the equation \(x^2 - p'x + q' = 0\). ### Step 1: Identify the roots and their properties From the first quadratic equation \(x^2 - px + q = 0\): - The sum of the roots \(\alpha + \beta = p\) - The product of the roots \(\alpha \beta = q\) From the second quadratic equation \(x^2 - p'x + q' = 0\): - The sum of the roots \(\alpha' + \beta' = p'\) - The product of the roots \(\alpha' \beta' = q'\) ### Step 2: Expand the expression Now we will expand the expression: \[ (\alpha - \alpha')^2 + (\beta - \alpha')^2 + (\alpha - \beta')^2 + (\beta - \beta')^2 \] Using the identity \((a - b)^2 = a^2 - 2ab + b^2\), we can expand each term: 1. \((\alpha - \alpha')^2 = \alpha^2 - 2\alpha\alpha' + \alpha'^2\) 2. \((\beta - \alpha')^2 = \beta^2 - 2\beta\alpha' + \alpha'^2\) 3. \((\alpha - \beta')^2 = \alpha^2 - 2\alpha\beta' + \beta'^2\) 4. \((\beta - \beta')^2 = \beta^2 - 2\beta\beta' + \beta'^2\) ### Step 3: Combine the expanded terms Now, we combine all the expanded terms: \[ = (\alpha^2 + \beta^2 + \alpha'^2 + \beta'^2) - 2(\alpha\alpha' + \beta\alpha' + \alpha\beta' + \beta\beta') \] ### Step 4: Use the identities for sums and products We know from the properties of roots: - \(\alpha^2 + \beta^2 = (\alpha + \beta)^2 - 2\alpha\beta = p^2 - 2q\) - \(\alpha'^2 + \beta'^2 = (\alpha' + \beta')^2 - 2\alpha'\beta' = p'^2 - 2q'\) Substituting these into our expression gives: \[ = (p^2 - 2q) + (p'^2 - 2q') - 2(\alpha\alpha' + \beta\alpha' + \alpha\beta' + \beta\beta') \] ### Step 5: Simplify the cross terms The cross terms can be grouped as follows: \[ = p^2 + p'^2 - 2q - 2q' - 2(\alpha\alpha' + \beta\alpha' + \alpha\beta' + \beta\beta') \] ### Step 6: Final expression Thus, the final expression we need to evaluate is: \[ = p^2 + p'^2 - 2(q + q') - 2(\alpha\alpha' + \beta\alpha' + \alpha\beta' + \beta\beta') \] ### Conclusion The value of the expression is: \[ = p^2 + p'^2 - 2(q + q') - 2(\alpha\alpha' + \beta\alpha' + \alpha\beta' + \beta\beta') \]
Doubtnut Promotions Banner Mobile Dark
|

Topper's Solved these Questions

  • THEORY OF QUADRATIC EQUATIONS

    ML KHANNA|Exercise Problem Set - 2|66 Videos
  • THEORY OF QUADRATIC EQUATIONS

    ML KHANNA|Exercise Problem Set - 2 (True And False)|4 Videos
  • THEORY OF QUADRATIC EQUATIONS

    ML KHANNA|Exercise Problem Set - 1 (True And False)|3 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 equation 3x^(2)-4x+2=0 , then the value of (alpha)/(beta)+(beta)/(alpha) is

If alpha,beta are the roots of 2x^(2)+x+7=0 find the value of alpha^(2)beta+alpha beta^(2)

Knowledge Check

  • If alpha and beta be the roots of x^(2)+px-q=0 and gamma, delta the roots of x^(2)+px+r=00 , then the value of (alpha-gamma) (alpha-delta) =(beta-gamma)(beta-delta) =

    A
    `q+r`
    B
    `r+q`
    C
    `p+q+r`
    D
    none
  • If alpha and beta be the roots of x^(2)+px+1=0 and gamma, delta the root of x^(2)+qx+1=0 , then the value (alpha-gamma) (beta-gamma) (alpha+delta) (beta + delta) is equal to

    A
    `p^(2)-q^(2)`
    B
    `q^(2)-p^(2)`
    C
    `p^(2)`
    D
    `q^(2)`
  • If alpha and beta are roots of x^2+px+2=0 and 1/alpha,1/beta are the roots of 2x^2+2qx+1=0 . Find the value of (alpha-1/alpha)(beta-1/beta)(alpha+1/beta)(beta+1/alpha)1

    A
    `9/4(9-p^2)`
    B
    `9/4(9+q^2)`
    C
    `9/4(9+p^2)`
    D
    `9/4(9-q^2)`
  • Similar Questions

    Explore conceptually related problems

    If alpha,beta are the roots of x^(2)-px+q=0 then the equation whose roots are alpha beta+alpha+beta,alpha beta-alpha-beta

    If alpha,beta are the roots of x^(2)-px+q. Find the value of the following: (alpha)/(beta)+(beta)/(alpha)

    If alpha,beta are roots of x^(2)-px+q=0 and alpha-2,beta+2 are roots of x^(2)-px+r=0 then prove that 16q+(r+4-q)^(2)=4p^(2)

    If alpha and beta are the roots of equation 2x^(2)-3x+5=0 then find the value of alpha^(2)beta+beta^(2)alpha

    If alpha,beta " are the roots of the equation "x^(2) - 2x - 1 =0, "then what is the value of " alpha^(2)beta^(-2)+alpha^(-2)beta^(2)