Home
Class 12
MATHS
If alpha and beta, alpha and gamma, alph...

If `alpha` and `beta`, `alpha` and `gamma`, `alpha` and `delta` are the roots of the equations `ax^(2)+2bx+c=0`, `2bx^(2)+cx+a=0` and `cx^(2)+ax+2b=0` respectively where `a`, `b`, `c` are positive real numbers, then `alpha+alpha^(2)` is equal to

A

`-1`

B

`1`

C

`0`

D

`abc`

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem, we need to analyze the three equations given in the question and find the value of \( \alpha + \alpha^2 \). ### Step 1: Write down the equations The roots of the equations are given as follows: 1. \( ax^2 + 2bx + c = 0 \) (roots: \( \alpha, \beta \)) 2. \( 2bx^2 + cx + a = 0 \) (roots: \( \alpha, \gamma \)) 3. \( cx^2 + ax + 2b = 0 \) (roots: \( \alpha, \delta \)) ### Step 2: Substitute \( \alpha \) into each equation Since \( \alpha \) is a root of all three equations, we can substitute \( \alpha \) into each equation: 1. From the first equation: \[ a\alpha^2 + 2b\alpha + c = 0 \] 2. From the second equation: \[ 2b\alpha^2 + c\alpha + a = 0 \] 3. From the third equation: \[ c\alpha^2 + a\alpha + 2b = 0 \] ### Step 3: Add the three equations Now, we add all three equations together: \[ (a\alpha^2 + 2b\alpha + c) + (2b\alpha^2 + c\alpha + a) + (c\alpha^2 + a\alpha + 2b) = 0 \] ### Step 4: Combine like terms Combining the terms gives us: \[ (a + 2b + c)\alpha^2 + (2b + c + a)\alpha + (c + a + 2b) = 0 \] ### Step 5: Factor out common terms We can factor out \( (a + 2b + c) \): \[ (a + 2b + c)(\alpha^2 + \alpha + 1) = 0 \] ### Step 6: Analyze the factor Since \( a, b, c \) are positive real numbers, \( a + 2b + c \) cannot be zero. Therefore, we must have: \[ \alpha^2 + \alpha + 1 = 0 \] ### Step 7: Solve for \( \alpha + \alpha^2 \) The equation \( \alpha^2 + \alpha + 1 = 0 \) can be rearranged to find \( \alpha + \alpha^2 \): \[ \alpha + \alpha^2 = -1 \] ### Conclusion Thus, the value of \( \alpha + \alpha^2 \) is: \[ \boxed{-1} \]

To solve the problem, we need to analyze the three equations given in the question and find the value of \( \alpha + \alpha^2 \). ### Step 1: Write down the equations The roots of the equations are given as follows: 1. \( ax^2 + 2bx + c = 0 \) (roots: \( \alpha, \beta \)) 2. \( 2bx^2 + cx + a = 0 \) (roots: \( \alpha, \gamma \)) 3. \( cx^2 + ax + 2b = 0 \) (roots: \( \alpha, \delta \)) ...
Promotional Banner

Topper's Solved these Questions

  • THEORY OF EQUATIONS

    CENGAGE ENGLISH|Exercise Comprehension|12 Videos
  • THEORY OF EQUATIONS

    CENGAGE ENGLISH|Exercise Multiple Correct Answer|6 Videos
  • STRAIGHT LINES

    CENGAGE ENGLISH|Exercise ARCHIVES (NUMERICAL VALUE TYPE)|1 Videos
  • THREE DIMENSIONAL GEOMETRY

    CENGAGE ENGLISH|Exercise All Questions|294 Videos

Similar Questions

Explore conceptually related problems

If alpha beta( alpha lt beta) are two distinct roots of the equation. ax^(2)+bx+c=0 , then

If alpha and beta (alpha lt beta) are the roots of the equation x^(2) + bx + c = 0 , where c lt 0 lt b , then

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

If alpha and beta are the roots of the equation ax ^(2) + bx + c=0,a,b, c in R , alpha ne 0 then which is (are) correct:

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

If alpha and beta are the roots of the quadratic equation ax^(2)+bx+1 , then the value of 2alpha^(2)beta^(2) is

Let alpha , beta (a lt b) be the roots of the equation ax^(2)+bx+c=0 . If lim_(xtom) (|ax^(2)+bx+c|)/(ax^(2)+bx+c)=1 then

Two different real numbers alpha and beta are the roots of the quadratic equation ax ^(2) + c=0 a,c ne 0, then alpha ^(3) + beta ^(3) is:

If alpha, beta are the roots of the equation ax^(2) +2bx +c =0 and alpha +h, beta + h are the roots of the equation Ax^(2) +2Bx + C=0 then

If alpha and beta are roots of the equation ax^2+bx +c=0 , then lim_(xrarralpha) (1+ax^2+bx+c)^(1//x-alpha) , is