Home
Class 12
MATHS
If the equations x^(2)+2lambdax+lambda^(...

If the equations `x^(2)+2lambdax+lambda^(2)+1=0`, `lambda in R` and `ax^(2)+bx+c=0` , where `a`, `b`, `c` are lengths of sides of triangle have a common root, then the possible range of values of `lambda` is

A

`(0,2)`

B

`(sqrt(3),3)`

C

`(2sqrt(2),3sqrt(2))`

D

`(0,oo)`

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem, we need to find the range of values of \(\lambda\) such that the equations \(x^2 + 2\lambda x + \lambda^2 + 1 = 0\) and \(ax^2 + bx + c = 0\) (where \(a\), \(b\), and \(c\) are the lengths of the sides of a triangle) have a common root. ### Step-by-step Solution: 1. **Identify the first equation**: The first equation is: \[ x^2 + 2\lambda x + \lambda^2 + 1 = 0 \] This can be rewritten as: \[ (x + \lambda)^2 + 1 = 0 \] This indicates that the roots are complex and occur in conjugate pairs. 2. **Let the common root be \(r\)**: Since both equations share a common root \(r\), we can substitute \(r\) into both equations. 3. **Set up the second equation**: The second equation is: \[ ax^2 + bx + c = 0 \] Substituting \(r\) into this equation gives: \[ ar^2 + br + c = 0 \] 4. **Express \(a\), \(b\), and \(c\) in terms of \(k\)**: Since \(a\), \(b\), and \(c\) are the sides of a triangle, we can express them in terms of a common variable \(k\): \[ a = k, \quad b = 2\lambda k, \quad c = (\lambda^2 + 1)k \] 5. **Substitute \(a\), \(b\), and \(c\) into the second equation**: Replacing \(a\), \(b\), and \(c\) in the second equation gives: \[ kr^2 + (2\lambda k)r + (\lambda^2 + 1)k = 0 \] Dividing through by \(k\) (assuming \(k \neq 0\)): \[ r^2 + 2\lambda r + (\lambda^2 + 1) = 0 \] 6. **Establish inequalities based on triangle properties**: For \(a\), \(b\), and \(c\) to form a triangle, the triangle inequality must hold: \[ a + b > c, \quad a + c > b, \quad b + c > a \] Substituting the values: - \(k + 2\lambda k > (\lambda^2 + 1)k\) - \(k + (\lambda^2 + 1)k > 2\lambda k\) - \(2\lambda k + (\lambda^2 + 1)k > k\) 7. **Simplify the inequalities**: From the first inequality: \[ 1 + 2\lambda > \lambda^2 + 1 \implies 2\lambda > \lambda^2 \implies \lambda^2 - 2\lambda < 0 \] Factoring gives: \[ \lambda(\lambda - 2) < 0 \] 8. **Determine the range of \(\lambda\)**: The inequality \(\lambda(\lambda - 2) < 0\) indicates that \(\lambda\) must lie between the roots \(0\) and \(2\): \[ 0 < \lambda < 2 \] ### Conclusion: The possible range of values for \(\lambda\) is: \[ \lambda \in (0, 2) \]

To solve the problem, we need to find the range of values of \(\lambda\) such that the equations \(x^2 + 2\lambda x + \lambda^2 + 1 = 0\) and \(ax^2 + bx + c = 0\) (where \(a\), \(b\), and \(c\) are the lengths of the sides of a triangle) have a common root. ### Step-by-step Solution: 1. **Identify the first equation**: The first equation is: \[ x^2 + 2\lambda x + \lambda^2 + 1 = 0 ...
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 the equation x^(2)+2x+3=0 and ax^(2)+bx+c=0, a,b,c in R have a common root, then a:b:c is

If the equation x^(2 )+ 2x + 3 = 0 and ax^(2) +bx+c=0, a, b, c in R , have a common root, then a : b:c is

The equation ax^(2) +bx+ c=0, where a,b,c are the side of a DeltaABC, and the equation x^(2) +sqrt2x+1=0 have a common root. Find measure for angle C.

If the equations 2x^(2)-7x+1=0 and ax^(2)+bx+2=0 have a common root, then

If equations ax^(2)-bx+c=0 (where a,b,c epsilonR and a!=0 ) and x^(2)+2x+3=0 have a common root, then show that a:b:c=1:2:3

If ax^(2)+bx+c=0 and 5x^(2)+6x+12=0 have a common root where a, b and c are sides of a triangle ABC , then

IF the equation ax^2 + 2bx + 3c =0 and 3x^(2)+8x+15=0 have a common root , where a,b,c are the length of the sides of a Delta ABC , then sin ^2 A + sin ^2 B+ sin ^(2) C=

If in any triangle, the area DeltaABC le(b^(2)+c^(2))/(lambda) , then the largest possible numerical value of lambda is

If sin theta and -cos theta are the roots of the equation ax^(2) - bx - c = 0 , where a, b, and c are the sides of a triangle ABC, then cos B is equal to

If the equation ax^(2) + bx + c = 0 and 2x^(2) + 3x + 4 = 0 have a common root, then a : b : c