मराठी

Find the Inverse by Using Elementary Row Transformations: ⎡ ⎢ ⎣ 0 1 2 1 2 3 3 1 1 ⎤ ⎥ ⎦ - Mathematics

Advertisements
Advertisements

प्रश्न

Find the inverse by using elementary row transformations:

\[\begin{bmatrix}0 & 1 & 2 \\ 1 & 2 & 3 \\ 3 & 1 & 1\end{bmatrix}\]

बेरीज

उत्तर

\[A = \begin{bmatrix}0 & 1 & 2 \\ 1 & 2 & 3 \\ 3 & 1 & 1\end{bmatrix}\]
We know
\[A = IA \]
\[ \Rightarrow \begin{bmatrix}0 & 1 & 2 \\ 1 & 2 & 3 \\ 3 & 1 & 1\end{bmatrix} = \begin{bmatrix}1 & 0 & 0 \\ 0 & 1 & 0 \\ 0 & 0 & 1\end{bmatrix} A\]
\[ \Rightarrow \begin{bmatrix}0 & 1 & 2 \\ - 2 & 1 & 2 \\ 3 & 1 & 1\end{bmatrix} = \begin{bmatrix}1 & 0 & 0 \\ 0 & 1 & - 1 \\ 0 & 0 & 1\end{bmatrix} A \left[\text{ Applying }R_2 \to R_2 - R_3 \right]\]
\[ \Rightarrow \begin{bmatrix}- 3 & 0 & 1 \\ - 2 & 1 & 2 \\ 3 & 1 & 1\end{bmatrix} = \begin{bmatrix}1 & 0 & - 1 \\ 0 & 1 & - 1 \\ 0 & 0 & 1\end{bmatrix} A \left[\text{ Applying }R_1 \to R_1 - R_3 \right]\]
\[ \Rightarrow \begin{bmatrix}- 3 & 0 & 1 \\ - 2 & 1 & 2 \\ 0 & 1 & 2\end{bmatrix} = \begin{bmatrix}1 & 0 & - 1 \\ 0 & 1 & - 1 \\ 1 & 0 & 0\end{bmatrix} A \left[\text{ Applying }R_3 \to R_3 + R_1 \right]\]
\[ \Rightarrow \begin{bmatrix}- 3 & 0 & 1 \\ 0 & 3 & 4 \\ 0 & 1 & 2\end{bmatrix} = \begin{bmatrix}1 & 0 & - 1 \\ - 2 & 3 & - 1 \\ 1 & 0 & 0\end{bmatrix} A \left[\text{ Applying }R_2 \to 3 R_2 - 2 R_1 \right]\]
\[ \Rightarrow \begin{bmatrix}- 3 & 0 & 1 \\ 0 & 3 & 4 \\ 0 & - 2 & - 2\end{bmatrix} = \begin{bmatrix}1 & 0 & - 1 \\ - 2 & 3 & - 1 \\ 3 & - 3 & 1\end{bmatrix} A \left[\text{ Applying }R_3 \to R_3 - R_2 \right]\]
\[ \Rightarrow \begin{bmatrix}- 3 & 0 & 1 \\ 0 & 3 & 4 \\ 0 & 1 & 1\end{bmatrix} = \begin{bmatrix}1 & 0 & - 1 \\ - 2 & 3 & - 1 \\ \frac{- 3}{2} & \frac{3}{2} & \frac{- 1}{2}\end{bmatrix} A \left[\text{ Applying }R_3 \to - \frac{1}{2} R_3 \right]\]
\[ \Rightarrow \begin{bmatrix}- 3 & 0 & 1 \\ 0 & - 1 & 0 \\ 0 & 1 & 1\end{bmatrix} = \begin{bmatrix}1 & 0 & - 1 \\ 4 & - 3 & 1 \\ \frac{- 3}{2} & \frac{3}{2} & \frac{- 1}{2}\end{bmatrix} A \left[ \text{ Applying }R_2 \to R_2 - 4 R_3 \right]\]
\[ \Rightarrow \begin{bmatrix}- 3 & 0 & 1 \\ 0 & - 1 & 0 \\ 0 & 0 & 1\end{bmatrix} = \begin{bmatrix}1 & 0 & - 1 \\ 4 & - 3 & 1 \\ \frac{5}{2} & \frac{- 3}{2} & \frac{1}{2}\end{bmatrix} A \left[ \text{ Applying }R_3 \to R_3 + R_2 \right]\]
\[ \Rightarrow \begin{bmatrix}- 3 & 0 & 0 \\ 0 & - 1 & 0 \\ 0 & 0 & 1\end{bmatrix} = \begin{bmatrix}- \frac{3}{2} & \frac{3}{2} & - \frac{3}{2} \\ 4 & - 3 & 1 \\ \frac{5}{2} & \frac{- 3}{2} & \frac{1}{2}\end{bmatrix} A \left[\text{ Applying }R_1 \to R_1 - R_3 \right]\]
\[ \Rightarrow \begin{bmatrix}1 & 0 & 0 \\ 0 & - 1 & 0 \\ 0 & 0 & 1\end{bmatrix} = \begin{bmatrix}\frac{1}{2} & \frac{- 1}{2} & \frac{1}{2} \\ 4 & - 3 & 1 \\ \frac{5}{2} & \frac{- 3}{2} & \frac{1}{2}\end{bmatrix} A \left[\text{ Applying }R_1 \to \frac{- 1}{3} R_1 \right]\]
\[ \Rightarrow \begin{bmatrix}1 & 0 & 0 \\ 0 & 1 & 0 \\ 0 & 0 & 1\end{bmatrix} = \begin{bmatrix}\frac{1}{2} & \frac{- 1}{2} & \frac{1}{2} \\ - 4 & 3 & - 1 \\ \frac{5}{2} & \frac{- 3}{2} & \frac{1}{2}\end{bmatrix} A \left[\text{ Applying }R_2 \to - R_2 \right]\]

shaalaa.com
  या प्रश्नात किंवा उत्तरात काही त्रुटी आहे का?
पाठ 7: Adjoint and Inverse of a Matrix - Exercise 7.2 [पृष्ठ ३४]

APPEARS IN

आरडी शर्मा Mathematics [English] Class 12
पाठ 7 Adjoint and Inverse of a Matrix
Exercise 7.2 | Q 6 | पृष्ठ ३४

संबंधित प्रश्‍न

Verify A (adj A) = (adj A) A = |A|I.

`[(2,3),(-4,-6)]`


For the matrix A = `[(3,2),(1,1)]` find the numbers a and b such that A2 + aA + bI = O.


If A = `[(2,-1,1),(-1,2,-1),(1,-1,2)]` verify that A3 − 6A2 + 9A − 4I = O and hence find A−1


If A is an invertible matrix of order 2, then det (A−1) is equal to ______.


Let A = `[(1,-2,1),(-2,3,1),(1,1,5)]` verify that

  1. [adj A]–1 = adj (A–1)
  2. (A–1)–1 = A

Let A = `[(1, sin theta, 1),(-sin theta,1,sin 1),(-1, -sin theta, 1)]` where 0 ≤ θ≤ 2π, then ______.


Find the adjoint of the following matrix:
\[\begin{bmatrix}a & b \\ c & d\end{bmatrix}\]

Verify that (adj A) A = |A| I = A (adj A) for the above matrix.

Find the inverse of the following matrix.

\[\begin{bmatrix}1 & 2 & 5 \\ 1 & - 1 & - 1 \\ 2 & 3 & - 1\end{bmatrix}\]

Find the inverse of the following matrix.

\[\begin{bmatrix}2 & - 1 & 1 \\ - 1 & 2 & - 1 \\ 1 & - 1 & 2\end{bmatrix}\]

Let
\[F \left( \alpha \right) = \begin{bmatrix}\cos \alpha & - \sin \alpha & 0 \\ \sin \alpha & \cos \alpha & 0 \\ 0 & 0 & 1\end{bmatrix}\text{ and }G\left( \beta \right) = \begin{bmatrix}\cos \beta & 0 & \sin \beta \\ 0 & 1 & 0 \\ - \sin \beta & 0 & \cos \beta\end{bmatrix}\]

Show that

(i) \[\left[ F \left( \alpha \right) \right]^{- 1} = F \left( - \alpha \right)\]
(ii) \[\left[ G \left( \beta \right) \right]^{- 1} = G \left( - \beta \right)\]
(iii) \[\left[ F \left( \alpha \right)G \left( \beta \right) \right]^{- 1} = G \left( - \beta \right)F \left( - \alpha \right)\]

Show that the matrix, \[A = \begin{bmatrix}1 & 0 & - 2 \\ - 2 & - 1 & 2 \\ 3 & 4 & 1\end{bmatrix}\]  satisfies the equation,  \[A^3 - A^2 - 3A - I_3 = O\] . Hence, find A−1.


Solve the matrix equation \[\begin{bmatrix}5 & 4 \\ 1 & 1\end{bmatrix}X = \begin{bmatrix}1 & - 2 \\ 1 & 3\end{bmatrix}\], where X is a 2 × 2 matrix.


Find the matrix X for which 

\[\begin{bmatrix}3 & 2 \\ 7 & 5\end{bmatrix} X \begin{bmatrix}- 1 & 1 \\ - 2 & 1\end{bmatrix} = \begin{bmatrix}2 & - 1 \\ 0 & 4\end{bmatrix}\]

 


Find the matrix X satisfying the equation 

\[\begin{bmatrix}2 & 1 \\ 5 & 3\end{bmatrix} X \begin{bmatrix}5 & 3 \\ 3 & 2\end{bmatrix} = \begin{bmatrix}1 & 0 \\ 0 & 1\end{bmatrix} .\]

\[\text{ If }A^{- 1} = \begin{bmatrix}3 & - 1 & 1 \\ - 15 & 6 & - 5 \\ 5 & - 2 & 2\end{bmatrix}\text{ and }B = \begin{bmatrix}1 & 2 & - 2 \\ - 1 & 3 & 0 \\ 0 & - 2 & 1\end{bmatrix},\text{ find }\left( AB \right)^{- 1} .\]

Find the inverse by using elementary row transformations:

\[\begin{bmatrix}2 & 3 & 1 \\ 2 & 4 & 1 \\ 3 & 7 & 2\end{bmatrix}\]


Find the inverse by using elementary row transformations:

\[\begin{bmatrix}1 & 1 & 2 \\ 3 & 1 & 1 \\ 2 & 3 & 1\end{bmatrix}\]


Find the inverse by using elementary row transformations:

\[\begin{bmatrix}2 & - 1 & 4 \\ 4 & 0 & 7 \\ 3 & - 2 & 7\end{bmatrix}\]


Find the inverse by using elementary row transformations:

\[\begin{bmatrix}3 & 0 & - 1 \\ 2 & 3 & 0 \\ 0 & 4 & 1\end{bmatrix}\]    


If A is symmetric matrix, write whether AT is symmetric or skew-symmetric.


If \[A = \begin{bmatrix}2 & 3 \\ 5 & - 2\end{bmatrix}\] , write  \[A^{- 1}\] in terms of A.


If A is an invertible matrix of order 3, then which of the following is not true ?


For any 2 × 2 matrix, if \[A \left( adj A \right) = \begin{bmatrix}10 & 0 \\ 0 & 10\end{bmatrix}\] , then |A| is equal to ______ .


If A satisfies the equation \[x^3 - 5 x^2 + 4x + \lambda = 0\] then A-1 exists if _____________ .


If for the matrix A, A3 = I, then A−1 = _____________ .


For non-singular square matrix A, B and C of the same order \[\left( A B^{- 1} C \right) =\] ______________ .


If \[A^2 - A + I = 0\], then the inverse of A is __________ .


If \[A = \begin{bmatrix}2 & 3 \\ 5 & - 2\end{bmatrix}\]  be such that \[A^{- 1} = kA\], then k equals ___________ .


If \[A = \begin{bmatrix}2 & - 3 & 5 \\ 3 & 2 & - 4 \\ 1 & 1 & - 2\end{bmatrix}\], find A−1 and hence solve the system of linear equations 2x − 3y + 5z = 11, 3x + 2y − 4z = −5, x + y + 2z = −3


If A = `[(0, 1, 3),(1, 2, x),(2, 3, 1)]`, A–1 = `[(1/2, -4, 5/2),(-1/2, 3, -3/2),(1/2, y, 1/2)]` then x = 1, y = –1.


|A–1| ≠ |A|–1, where A is non-singular matrix.


|adj. A| = |A|2, where A is a square matrix of order two.


Find the value of x for which the matrix A `= [(3 - "x", 2, 2),(2,4 - "x", 1),(-2,- 4,-1 - "x")]` is singular.


A and B are invertible matrices of the same order such that |(AB)-1| = 8, If |A| = 2, then |B| is ____________.


If A is a square matrix of order 3, |A′| = −3, then |AA′| = ______.


If for a square matrix A, A2 – A + I = 0, then A–1 equals ______.


To raise money for an orphanage, students of three schools A, B and C organised an exhibition in their residential colony, where they sold paper bags, scrap books and pastel sheets made by using recycled paper. Student of school A sold 30 paper bags, 20 scrap books and 10 pastel sheets and raised ₹ 410. Student of school B sold 20 paper bags, 10 scrap books and 20 pastel sheets and raised ₹ 290. Student of school C sold 20 paper bags, 20 scrap books and 20 pastel sheets and raised ₹ 440.

Answer the following question:

  1. Translate the problem into a system of equations.
  2. Solve the system of equation by using matrix method.
  3. Hence, find the cost of one paper bag, one scrap book and one pastel sheet.

Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×