Home
Class 12
MATHS
If a,b,c are non-coplanar vectors and la...

If a,b,c are non-coplanar vectors and `lamda` is a real number, then the vectors `a+2b+3c,lamdab+4c and (2lamda-1)c` are non-coplanar for

A

all value of `lamda`

B

all except one value of `lamda`

C

all except two value of `lamda`

D

no value of `lamda`

Text Solution

AI Generated Solution

The correct Answer is:
To determine the conditions under which the vectors \( \mathbf{a} + 2\mathbf{b} + 3\mathbf{c} \), \( \lambda \mathbf{b} + 4\mathbf{c} \), and \( (2\lambda - 1)\mathbf{c} \) are non-coplanar, we can use the determinant method. Vectors are non-coplanar if the determinant of their coefficients is non-zero. ### Step-by-step Solution: 1. **Identify the Vectors**: We have three vectors: - \( \mathbf{v_1} = \mathbf{a} + 2\mathbf{b} + 3\mathbf{c} \) - \( \mathbf{v_2} = \lambda \mathbf{b} + 4\mathbf{c} \) - \( \mathbf{v_3} = (2\lambda - 1)\mathbf{c} \) 2. **Write the Coefficients**: The coefficients of \( \mathbf{a}, \mathbf{b}, \mathbf{c} \) in these vectors can be arranged into a matrix: \[ \begin{bmatrix} 1 & 2 & 3 \\ 0 & \lambda & 4 \\ 0 & 0 & 2\lambda - 1 \end{bmatrix} \] 3. **Calculate the Determinant**: We need to compute the determinant of this matrix: \[ \text{Det} = \begin{vmatrix} 1 & 2 & 3 \\ 0 & \lambda & 4 \\ 0 & 0 & 2\lambda - 1 \end{vmatrix} \] Since the matrix is upper triangular, the determinant is the product of the diagonal elements: \[ \text{Det} = 1 \cdot \lambda \cdot (2\lambda - 1) = \lambda(2\lambda - 1) \] 4. **Set the Determinant Not Equal to Zero**: For the vectors to be non-coplanar, we require: \[ \lambda(2\lambda - 1) \neq 0 \] 5. **Find the Values of \( \lambda \)**: The determinant is zero when: - \( \lambda = 0 \) - \( 2\lambda - 1 = 0 \) which gives \( \lambda = \frac{1}{2} \) 6. **Conclusion**: Therefore, the vectors are non-coplanar for all values of \( \lambda \) except \( \lambda = 0 \) and \( \lambda = \frac{1}{2} \). ### Final Answer: The vectors \( \mathbf{a} + 2\mathbf{b} + 3\mathbf{c} \), \( \lambda \mathbf{b} + 4\mathbf{c} \), and \( (2\lambda - 1)\mathbf{c} \) are non-coplanar for all values of \( \lambda \) except \( \lambda = 0 \) and \( \lambda = \frac{1}{2} \).

To determine the conditions under which the vectors \( \mathbf{a} + 2\mathbf{b} + 3\mathbf{c} \), \( \lambda \mathbf{b} + 4\mathbf{c} \), and \( (2\lambda - 1)\mathbf{c} \) are non-coplanar, we can use the determinant method. Vectors are non-coplanar if the determinant of their coefficients is non-zero. ### Step-by-step Solution: 1. **Identify the Vectors**: We have three vectors: - \( \mathbf{v_1} = \mathbf{a} + 2\mathbf{b} + 3\mathbf{c} \) - \( \mathbf{v_2} = \lambda \mathbf{b} + 4\mathbf{c} \) ...
Promotional Banner

Topper's Solved these Questions

  • VECTOR ALGEBRA

    ARIHANT MATHS|Exercise Exercise (Subjective Type Questions)|8 Videos
  • TRIGONOMETRIC FUNCTIONS AND IDENTITIES

    ARIHANT MATHS|Exercise Exercise (Questions Asked In Previous 13 Years Exam)|19 Videos

Similar Questions

Explore conceptually related problems

If a,b and c are non-coplanar vectors and lamda is a real number, then the vectors a+2b+3c,lamdab+muc and (2lamda-1)c are coplanar when

If a,b,c are non coplanner vectors and lambda is a real no.then the vector a +2b+3c,lambda b+4c and (2 lambda-1) c are non coplanner for:-

IF bara,barb,barc are non-coplanar vectors and lamda is a real number then the vectors bara+2barb+3barc,lamdabarb+4barc and(2lamda-1)barc are non coplanar for

If veca, vecb, vecc are non coplanar vectors and lamda is a real number, then the vectors veca+2vecb+3vecc, lamdavecb+4vec and (2lamda-1)vecc are non coplanar for

If bara,barb,barc are non coplanar vectros and lamda is a real number then the vectors bar+2barb+3barc,lamda barb+4barc and (2lamda-1)barc are non coplanar for (A) all values of lamda (B) non value of lamda (C) all except two values of lamda (D) all except one vaue of lamda

If veca,vecb,vecc are noncoplanar vectors and lamda is a real number, then the vectors veca+2vecb+3vecc, lamda vecb+4vecc and (2lamda-1)vecc are non coplanar of (A) all values of lamda (B) all except one values of lamda (C) all except two values of lamda (D) no value of lamda

If vec a,vec b,vec c are non-coplanar vectors and lambda is a real number then then vectors vec a+2vec b+3vec c,lambdavec b+4vec c and (2 lambda-1)vec c are non-coplanar for