Home
Class 12
MATHS
The system of linear equations lambdax...

The system of linear equations
`lambdax+2y+2z=5`
`2lambda x+3y+5z=8`
`4x+lambday+6z=10` has :

A

no solution when `lambda`=2

B

infinitely many solutions when `lambda=2`

C

no solution when `lambda=8`

D

infinite solution when `lambda=-8`

Text Solution

AI Generated Solution

The correct Answer is:
To determine the conditions under which the system of linear equations has no solution or infinitely many solutions, we can analyze the given equations step by step. ### Given Equations: 1. \( \lambda x + 2y + 2z = 5 \) (Equation 1) 2. \( 2\lambda x + 3y + 5z = 8 \) (Equation 2) 3. \( 4x + \lambda y + 6z = 10 \) (Equation 3) ### Step 1: Write the system in matrix form We can represent the system of equations in the form of a matrix \( A \) and a vector \( b \): \[ A = \begin{pmatrix} \lambda & 2 & 2 \\ 2\lambda & 3 & 5 \\ 4 & \lambda & 6 \end{pmatrix}, \quad b = \begin{pmatrix} 5 \\ 8 \\ 10 \end{pmatrix} \] ### Step 2: Find the rank of matrix \( A \) To find the rank of the matrix \( A \), we will perform row operations to reduce it to row echelon form. 1. Start with the original matrix: \[ \begin{pmatrix} \lambda & 2 & 2 \\ 2\lambda & 3 & 5 \\ 4 & \lambda & 6 \end{pmatrix} \] 2. Replace Row 2 with Row 2 - 2 * Row 1: \[ R_2 \rightarrow R_2 - 2R_1 \] This gives: \[ \begin{pmatrix} \lambda & 2 & 2 \\ 0 & 3 - 4 & 5 - 4 \\ 4 & \lambda & 6 \end{pmatrix} = \begin{pmatrix} \lambda & 2 & 2 \\ 0 & -1 & 1 \\ 4 & \lambda & 6 \end{pmatrix} \] 3. Replace Row 3 with Row 3 - \( \frac{4}{\lambda} \) * Row 1 (if \( \lambda \neq 0 \)): \[ R_3 \rightarrow R_3 - \frac{4}{\lambda}R_1 \] This gives: \[ \begin{pmatrix} \lambda & 2 & 2 \\ 0 & -1 & 1 \\ 0 & \lambda - \frac{8}{\lambda} & 6 - \frac{8}{\lambda} \end{pmatrix} \] ### Step 3: Analyze the rank conditions To determine if the system has no solution or infinitely many solutions, we need to check the rank of the augmented matrix \( [A|b] \): \[ [A|b] = \begin{pmatrix} \lambda & 2 & 2 & | & 5 \\ 2\lambda & 3 & 5 & | & 8 \\ 4 & \lambda & 6 & | & 10 \end{pmatrix} \] ### Step 4: Conditions for no solution or infinitely many solutions - **No Solution**: This occurs when \( \text{rank}(A) < \text{rank}(A|b) \). - **Infinitely Many Solutions**: This occurs when \( \text{rank}(A) = \text{rank}(A|b) < \text{number of variables} \). ### Step 5: Calculate specific values of \( \lambda \) 1. If \( \lambda = 2 \): - Substitute \( \lambda = 2 \) into the matrix and check the ranks. - The rank of \( A \) becomes 2, while the rank of \( [A|b] \) becomes 3, indicating no solution. 2. If \( \lambda \neq 2 \): - The ranks may be equal or differ depending on the values of \( \lambda \). ### Conclusion From the analysis, we find that: - The system has **no solution** when \( \lambda = 2 \). - For other values of \( \lambda \), we need to check specific cases to determine if we have infinitely many solutions. ### Final Answer The system of linear equations has: - **No solution** for \( \lambda = 2 \).
Promotional Banner

Topper's Solved these Questions

  • JEE (MAIN) 2020 QUESTION PAPER (7TH JAN - AFTERNOON)

    MCGROW HILL PUBLICATION|Exercise Multiple Choice Question|25 Videos
  • JEE (MAIN) 2020 QUESTIONS ( 9TH JAN-AFTERNOON)

    MCGROW HILL PUBLICATION|Exercise JEE (Main) 2020 Questions with Solutions Mathematics (9th Jan - Afternoon)|25 Videos

Similar Questions

Explore conceptually related problems

The system of linear equations x + lambda y-z =0, lambdax-y -z =0, x + y -lambda z =0 has a non-trivial solution for

The set of all values of lambda for which the system of linear equations x - 2y - 2z = lambdax x + 2y + z = lambday -x -y = lambdaz has a non-trivial solution

The system of linear equations x+lambday-z=0 lambdax-y-z=0 x+y-lambdaz=0 has a non-trivial solution for

The system of linear equations x+lambday-z=0 lambdax-y-z=0 x+y-lambdaz=0 has a non-trivial solution for : (1) infinitely many values of lambda . (2) exactly one value of lambda . (3) exactly two values of lambda . (4) exactly three values of lambda .

The number of real values of for which the system of linear equations 2x+4y- lambdaz =0 , 4x+lambday +2z=0 , lambdax + 2y+2z=0 has infinitely many solutions , is :

If the system of linear equations x+2y+3z=lambda x, 3x+y+2z=lambday , 2x+3y+z=lambdaz has non trivial solution then lambda=

The system of linear equations x-y-2z=6.-x+y+z=mu,lambda x+y+z=3 has

The system of linear equations lambda x + y + z = 3 x - y - 2z = 6 -x + y + z = mu has

The number of real values of lambda for which the system of linear equations 2x+4y-lambda z=0,4x+lambda y+2z=0,lambda x+2y+2z=0 has infinitely many solutions,is: (A)0(B)1(C)2(D)3

MCGROW HILL PUBLICATION-JEE (Main) 2020 QUESTION PAPER (8TH JAN-AFTERNOON)-Multiple Choice Questions
  1. If alpha and beta be the coefficients of x^4 and x^2 respectively in t...

    Text Solution

    |

  2. If a hyperbola passes through the point P(10,16) and it has vertices a...

    Text Solution

    |

  3. lim(x rarr 0)(int0^x tsin(10t)dt)/x is equal to

    Text Solution

    |

  4. If y = mx + c is a tangent to the circle (x – 3)^2 + y^2 = 1 and also ...

    Text Solution

    |

  5. Let alpha=(-1+isqrt(3))/2 and a=(1+alpha)sum(k=0)^(100) alpha^(2k),b=s...

    Text Solution

    |

  6. The mirror image of the point (1,2,3) in plane is (-7/3,-4/3, -1/3) . ...

    Text Solution

    |

  7. The length of the perpendicular from the origin,on the normal to the c...

    Text Solution

    |

  8. Which of the following statements is a tautology?

    Text Solution

    |

  9. Let I=int1^2 (dx)/sqrt(2x^3-9x^2+12x+4) then

    Text Solution

    |

  10. If A=((2,2),(9,4)) and I=((1,0),(0,1)), then 10A^(-1) is equal to :

    Text Solution

    |

  11. The area (in sq. units) of the region {(x,y) in R^2: x^2 le y le 3-2x}...

    Text Solution

    |

  12. Let the set of all function f: [0,1]toR, which are containous on [0,1]...

    Text Solution

    |

  13. The differential equation of the family of curves, x^(2)=4b(y+b),b in ...

    Text Solution

    |

  14. The system of linear equations lambdax+2y+2z=5 2lambda x+3y+5z=8 ...

    Text Solution

    |

  15. It the 10^(th) term of an A. P. is 1/20 and its 20^(th) term is 1/10, ...

    Text Solution

    |

  16. Let a line y = mx ( m gt 0) intersect the parabola, y^2 = 4x at a po...

    Text Solution

    |

  17. Let f(x) be a polynomial of degree 3 such that f(-1) = 10, f(1) = -6, ...

    Text Solution

    |

  18. If sqrt(sin alpha)/(sqrt(1+cos2 alpha))=1/7 and sqrt((1-cos2beta)/2)=1...

    Text Solution

    |

  19. The number of 4 letter words (with or without meaning) that can be for...

    Text Solution

    |

  20. sum(n=1)^7(n(n+1)(2n+1))/4 is equal to

    Text Solution

    |