मराठी

Find the Inverse by Using Elementary Row Transformations: [ 2 5 1 3 ] - Mathematics

Advertisements
Advertisements

प्रश्न

Find the inverse by using elementary row transformations:

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

बेरीज
Advertisements

उत्तर

\[A = \begin{bmatrix} 2 & 5\\1 & 3 \end{bmatrix}\]
We know
\[A = I A\]
\[ \Rightarrow \begin{bmatrix} 2 & 5\\1 & 3 \end{bmatrix} = \begin{bmatrix} 1 & 0\\0 & 1 \end{bmatrix}A\]
\[ \Rightarrow \begin{bmatrix} 2 - 1 & 5 - 3\\ 1 & 3 \end{bmatrix} = \begin{bmatrix} 1 - 0 & 0 - 1 \\ 0 & 1 \end{bmatrix}A [\text{ Applying }R_1 \to R_1 - R_2 ]\]
\[ \Rightarrow \begin{bmatrix} 1 & 2\\1 & 3 \end{bmatrix} = \begin{bmatrix} 1 & - 1\\0 & 1 \end{bmatrix}A\]
\[ \Rightarrow \begin{bmatrix} 1 & 2\\1 - 1 & 3 - 2 \end{bmatrix} = \begin{bmatrix} 1 & - 1\\0 - 1 & 1 + 1 \end{bmatrix}A [\text{ Applying }R_2 \to R_2 - R_1 ]\]
\[ \Rightarrow \begin{bmatrix} 1 & 2\\0 & 1 \end{bmatrix} = \begin{bmatrix} 1 & - 1 \\ - 1 & 2 \end{bmatrix}A\]
\[ \Rightarrow \begin{bmatrix} 1 & 0\\0 & 1 \end{bmatrix} = \begin{bmatrix} 1 + 2 & - 1 - 4 \\ - 1 & 2 \end{bmatrix}A [\text{ Applying }R_1 \to R_1 - 2 R_2 ]\]
\[ \Rightarrow \begin{bmatrix} 1 & 0\\0 & 1 \end{bmatrix} = \begin{bmatrix} 3 & - 5\\ - 1 & 2 \end{bmatrix}A\]
\[ \Rightarrow A^{- 1} = \begin{bmatrix} 3 & - 5\\ - 1 & 2 \end{bmatrix}\]

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 4 | 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 = 0.


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

Find the adjoint of the following matrix:
\[\begin{bmatrix}- 3 & 5 \\ 2 & 4\end{bmatrix}\]

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

Compute the adjoint of the following matrix:

\[\begin{bmatrix}2 & 0 & - 1 \\ 5 & 1 & 0 \\ 1 & 1 & 3\end{bmatrix}\]

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


Find the inverse of the following matrix:

\[\begin{bmatrix}a & b \\ c & \frac{1 + bc}{a}\end{bmatrix}\]

Find the inverse of the following matrix.

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

Find the inverse of the following matrix.

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

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

\[A = \begin{bmatrix}- 8 & 5 \\ 2 & 4\end{bmatrix}\] satisfies the equation \[A^2 + 4A - 42I = O\]. Hence, find A−1.

If \[A = \begin{bmatrix}3 & - 2 \\ 4 & - 2\end{bmatrix}\], find the value of \[\lambda\]  so that \[A^2 = \lambda A - 2I\]. Hence, find A−1.


If \[A = \begin{bmatrix}2 & - 1 & 1 \\ - 1 & 2 & - 1 \\ 1 & - 1 & 2\end{bmatrix}\].
Verify that \[A^3 - 6 A^2 + 9A - 4I = O\]  and hence find A−1.

If \[A = \begin{bmatrix}- 1 & 2 & 0 \\ - 1 & 1 & 1 \\ 0 & 1 & 0\end{bmatrix}\] , show that  \[A^2 = A^{- 1} .\]


Find the adjoint of the matrix \[A = \begin{bmatrix}- 1 & - 2 & - 2 \\ 2 & 1 & - 2 \\ 2 & - 2 & 1\end{bmatrix}\]  and hence show that \[A\left( adj A \right) = \left| A \right| I_3\]. 


\[\text{ If }A = \begin{bmatrix}0 & 1 & 1 \\ 1 & 0 & 1 \\ 1 & 1 & 0\end{bmatrix},\text{ find }A^{- 1}\text{ and show that }A^{- 1} = \frac{1}{2}\left( A^2 - 3I \right) .\]

Find the inverse by using elementary row transformations:

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


Find the inverse by using elementary row transformations:

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


Find the inverse by using elementary row transformations:

\[\begin{bmatrix}1 & 6 \\ - 3 & 5\end{bmatrix}\]


Find the inverse by using elementary row transformations:

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


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


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


The matrix \[\begin{bmatrix}5 & 10 & 3 \\ - 2 & - 4 & 6 \\ - 1 & - 2 & b\end{bmatrix}\] is a singular matrix, if the value of b is _____________ .


If d is the determinant of a square matrix A of order n, then the determinant of its adjoint is _____________ .


If \[A = \begin{bmatrix}2 & - 1 \\ 3 & - 2\end{bmatrix},\text{ then } A^n =\] ______________ .

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


Find A−1, if \[A = \begin{bmatrix}1 & 2 & 5 \\ 1 & - 1 & - 1 \\ 2 & 3 & - 1\end{bmatrix}\] . Hence solve the following system of linear equations:x + 2y + 5z = 10, x − y − z = −2, 2x + 3y − z = −11


Using matrix method, solve the following system of equations: 
x – 2y = 10, 2x + y + 3z = 8 and -2y + z = 7


If A and B are invertible matrices, then which of the following is not correct?


(A3)–1 = (A–1)3, where A is a square matrix and |A| ≠ 0.


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


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


If A = [aij] is a square matrix of order 2 such that aij = `{(1","  "when i" ≠ "j"),(0","  "when"  "i" = "j"):},` then A2 is ______.


If A is a square matrix of order 3 and |A| = 5, then |adj A| = ______.


If A = `[(1/sqrt(5), 2/sqrt(5)),((-2)/sqrt(5), 1/sqrt(5))]`, B = `[(1, 0),(i, 1)]`, i = `sqrt(-1)` and Q = ATBA, then the inverse of the matrix A. Q2021 AT is equal to ______.


If A = `[(0, 1),(0, 0)]`, then A2023 is equal to ______.


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×