हिंदी

If A = [sinαcosα-cosαsinα] then verify that A'A = I - Mathematics

Advertisements
Advertisements

प्रश्न

If A = `[(sin alpha, cos alpha), (-cos alpha, sin alpha)]` then verify that  A'A = I

योग
Advertisements

उत्तर

Given, A =  `[(sin  alpha, cos  alpha),(-cos  alpha, sin  alpha)]`

So, A' = `[(sin  alpha, -cos  alpha),(cos  alpha, sin  alpha)]`

Now, A' A = `[(sin  alpha, -cos  alpha),(cos  alpha, sin  alpha)] xx [(sin  alpha, cos  alpha),(-cos  alpha, sin  alpha)]`

`= [(sin^2 alpha+ cos^2 alpha, sin  alpha   cos alpha - cos alpha sin alpha),(cos  alpha  sin  alpha - sin  alpha  cos  alpha, cos^2 alpha + sin^2 alpha)]`

`= [(1, 0),(0,1)] = I`          ... [Because `sin^2 alpha + cos^2 alpha = 1`]

Hence, it is proved that, A'A = I

shaalaa.com
  क्या इस प्रश्न या उत्तर में कोई त्रुटि है?
अध्याय 3: Matrices - Exercise 3.3 [पृष्ठ ८९]

APPEARS IN

एनसीईआरटी Mathematics Part 1 and 2 [English] Class 12
अध्याय 3 Matrices
Exercise 3.3 | Q 6.2 | पृष्ठ ८९

संबंधित प्रश्न

Matrix A = `[(0,2b,-2),(3,1,3),(3a,3,-1)]`is given to be symmetric, find values of a and b


If A`((3,5),(7,9))`is written as A = P + Q, where P is a symmetric matrix and Q is skew symmetric matrix, then write the matrix P.

 


If `A = [(-1,2,3),(5,7,9),(-2,1,1)]  "and"  B = [(-4,1,-5),(1,2,0),(1,3,1)]` then verify that (A+ B)' = A' + B'


if `A = [(-1,2,3),(5,7,9),(-2,1,1)] and B = [(-4,1,-5),(1,2,0),(1,3,1)]` then verify that (A- B)' = A' - B'


if `A' [(3,4),(-1, 2),(0,1)] and B = [((-1,2,1),(1,2,3))]` then verify that (A + B)' = A' + B'


if `A' [(3,4),(-1, 2),(0,1)] and B = [((-1,2,1),(1,2,3))]` then verify that (A - B)' = A' - B'


if A' = `[(-2,3),(1,2)] and B = [(-1,0),(1,2)]`  then find (A + 2B)'


For the matrices A and B, verify that (AB)′ = B'A' where `A =[(1),(-4), (3)], B = [-1, 2  1]`


For the matrices A and B, verify that (AB)′ = B'A'  where `A =[(0), (1),(2)] , B =[1 , 5, 7]`


If A = `[(cos alpha, sin alpha), (-sin alpha, cos alpha)]` then verify that  A' A = I


Show that the matrix  A = `[(0,1,-1),(-1,0,1),(1,-1,0)]` is a skew symmetric matrix.


For the matrix A = `[(1,5),(6,7)]` verify that (A + A') is a symmetric matrix.


For the matrix A = `[(1,5),(6,7)]` verify that (A - A') is a skew symmetric matrix.


Find `1/2` (A + A')  and  `1/2` (A -A') When `A = [(0, a, b),(-a,0,c),(-b,-c,0)]`


Express the following matrices as the sum of a symmetric and a skew symmetric matrix:

`[(3,5),(1,-1)]`


Express the following matrices as the sum of a symmetric and a skew symmetric matrix:

`[(6, -2,2),(-2,3,-1),(2,-1,3)]`


Express the following matrices as the sum of a symmetric and a skew symmetric matrix:

`[(3,3,-1),(-2,-2,1),(-4,-5,2)]`


Express the following matrices as the sum of a symmetric and a skew symmetric matrix:

`[(1,5),(-1,2)]`


Show that the matrix B'AB is symmetric or skew symmetric according as A is symmetric or skew symmetric.


Find the values of x, y, z if the matrix `A = [(0,2y,z),(x,y,-z),(x , -y,z)]` satisfy the equation A'A = I.


If A and B are symmetric matrices of the same order, write whether AB − BA is symmetric or skew-symmetric or neither of the two.


Write a square matrix which is both symmetric as well as skew-symmetric.


For what value of x, is the matrix \[A = \begin{bmatrix}0 & 1 & - 2 \\ - 1 & 0 & 3 \\ x & - 3 & 0\end{bmatrix}\] a skew-symmetric matrix?


The matrix \[\begin{bmatrix}0 & 5 & - 7 \\ - 5 & 0 & 11 \\ 7 & - 11 & 0\end{bmatrix}\] is


If A is a square matrix, then AA is a


If A = [aij] is a square matrix of even order such that aij = i2 − j2, then 


If \[A = \begin{bmatrix}2 & 0 & - 3 \\ 4 & 3 & 1 \\ - 5 & 7 & 2\end{bmatrix}\]  is expressed as the sum of a symmetric and skew-symmetric matrix, then the symmetric matrix is  


If A and B are matrices of the same order, then ABT − BAT is a 


The matrix  \[A = \begin{bmatrix}0 & - 5 & 8 \\ 5 & 0 & 12 \\ - 8 & - 12 & 0\end{bmatrix}\] is a 

 

The matrix   \[A = \begin{bmatrix}1 & 0 & 0 \\ 0 & 2 & 0 \\ 0 & 0 & 4\end{bmatrix}\] is

 


If the matrix `((6,-"x"^2),(2"x"-15 , 10))` is symmetric, find the value of x.


Show that a matrix which is both symmetric and skew symmetric is a zero matrix.


Express the matrix A as the sum of a symmetric and a skew-symmetric matrix, where A = `[(2, 4, -6),(7, 3, 5),(1, -2, 4)]`


Let A = `[(2, 3),(-1, 2)]`. Then show that A2 – 4A + 7I = O. Using this result calculate A5 also.


If A and B are symmetric matrices of the same order, then (AB′ –BA′) is a ______.


If A and B are two skew-symmetric matrices of same order, then AB is symmetric matrix if ______.


If A = `[(0, 1),(1, 1)]` and B = `[(0, -1),(1, 0)]`, show that (A + B)(A – B) ≠ A2 – B2 


Show that A′A and AA′ are both symmetric matrices for any matrix A.


If A = `[(cosalpha, sinalpha),(-sinalpha, cosalpha)]`, and A–1 = A′, find value of α


If the matrix `[(0, "a", 3),(2, "b", -1),("c", 1, 0)]`, is a skew symmetric matrix, find the values of a, b and c.


Express the matrix `[(2, 3, 1),(1, -1, 2),(4, 1, 2)]` as the sum of a symmetric and a skew-symmetric matrix.


The matrix `[(1, 0, 0),(0, 2, 0),(0, 0, 4)]` is a ______.


The matrix `[(0, -5, 8),(5, 0, 12),(-8, -12, 0)]` is a ______.


______ matrix is both symmetric and skew-symmetric matrix.


Sum of two skew-symmetric matrices is always ______ matrix.


If A is a symmetric matrix, then A3 is a ______  matrix.


If A is a skew-symmetric matrix, then A2 is a ______.


If A and B are symmetric matrices, then AB – BA is a ______.


If A and B are symmetric matrices, then BA – 2AB is a ______.


If A is symmetric matrix, then B′AB is ______.


If each of the three matrices of the same order are symmetric, then their sum is a symmetric matrix.


If A and B are any two matrices of the same order, then (AB)′ = A′B′.


AA′ is always a symmetric matrix for any matrix A.


If A is skew-symmetric matrix, then A2 is a symmetric matrix.


If P is of order 2 x 3 and Q is of order 3 x 2, then PQ is of order ____________.


If A and B are symmetric matrices of the same order, then ____________.


If A and B are symmetric matrices of the same order, then ____________.


If A = `[(3, "x" - 1),(2"x" + 3, "x" + 2)]` is a symmetric matrix, then x = ____________.


If A is any square matrix, then which of the following is skew-symmetric?


The diagonal elements of a skew symmetric matrix are ____________.


If A, B are Symmetric matrices of same order, then AB – BA is a


If A = [aij] is a skew-symmetric matrix of order n, then ______.


If ax4 + bx3 + cx2 + dx + e = `|(2x, x - 1, x + 1),(x + 1, x^2 - x, x - 1),(x - 1, x + 1, 3x)|`, then the value of e is ______.


Let A and B be and two 3 × 3 matrices. If A is symmetric and B is skewsymmetric, then the matrix AB – BA is ______.


If `[(2, 0),(5, 4)]` = P + Q, where P is symmetric, and Q is a skew-symmetric matrix, then Q is equal to ______.


Number of symmetric matrices of order 3 × 3 with each entry 1 or – 1 is ______.


The value of |A|, if A = `[(0, 2x - 1, sqrt(x)),(1 - 2x, 0, 2sqrt(x)),(-sqrt(x), -2sqrt(x), 0)]`, where x ∈ R+, is ______.


For what value of k the matrix `[(0, k),(-6, 0)]` is a skew symmetric matrix?


If A and B are symmetric matrices of the same order, then AB – BA is ______.


Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×