Engineering Mathematics PDF
Engineering Mathematics PDF
Engineering Mathematics PDF
ENGINEERING MATHEMATI CS :
Types of Matrices
1. Row Matrix:
A matrix having only one row is called as “Row Matrix or Row Vector”.
e.g. [1 2 1],[1 0 2 3 −3],[𝑎] etc.
2. Column Matrix :
A matrix having only one column is called as “Column Matrix or Column vector”.
1
1
e.g. :[2] ,[ ] ,[𝑏] etc.
−1
3
Note that : A row or column matrix is also called as vector.
3. Null or Zero Matrix:
A matrix containing only zeroes is called as “Null or Zero Matrix”.
0 0 0 [0]
e.g. [ ] ,[ ] , etc.
0 0 0
4. Square Matrix:
A matrix is said to be “Square Matrix”, if number of rows is equal to number of
column in it.
3 0 2
1 0
[ ] , [0 1 0] , [4]1×1 etc.
0 1 2×2
2 0 3 3×3
5. Diagonal Matrix:
A square matrix is said to be “Diagonal Matrix”, if all its non-diagonal entries are zero
and atleast one diagonal element are non zero.
1 0 0
1 0
e.g. [ ] , [0 0 0] , 𝑒𝑡𝑐
0 5
0 0 2
6. Scalar Matrix :
A diagonal matrix in which all entries on principal diagonal are equal is called as
“Scalar Matrix”.
2 0 0
4 0
e.g. : e.g. [ ] , [0 2 0] , 𝑒𝑡𝑐
0 4
0 0 2
7. Unit Matrix or Identity Matrix:
A scalar matrix in which all entries on principal diagonal are unit (one) is called as
“Unit or Identity Matrix”.
1 𝑖𝑓 𝑖 = 𝑗
i.e., [𝑎𝑖𝑗 ] is a Identity, if 𝑎𝑖𝑗 ={
0 𝑖𝑓 𝑖 ≠ 𝑗
1 0 0
1 0
e.g. [ ] , [0 1 0] etc
0 1
0 0 1
8. Upper Triangular Matrix:
A matrix in which all entries below principal diagonal are zero is called as “Upper
triangular matrix”.
i.e., [𝑎𝑖𝑗 ] is a upper triangular, iff 𝑎𝑖𝑗 = 0 𝑖𝑓 𝑖 > 𝑗
1 2 3
1 2
e.g. :[ ] , [0 4 5] etc.
0 3
0 0 6
0 1 + 2𝑖 2 − 3𝑖
𝑎 𝑐 + 𝑑𝑖
e. g. 𝐴 = [−1 + 2𝑖 0 3 + 4𝑖 ] = −𝐴𝐻 , 𝐵 = [ ] = 𝐵𝐻 , 𝑒𝑡𝑐.
𝑐 − 𝑑𝑖 𝑏
2 + 3𝑖 −3 + 4𝑖 0
14. Skew – herimition Matrix:
A square complex matrix A is said to be “Skew – Herimitian matrix”
If 𝐴 = −𝐴𝐻 , where 𝐴𝐻 = ̅̅̅̅
𝐴𝑇
0 1 + 2𝑖 2 − 3𝑖
𝑎 𝑐 + 𝑑𝑖
e. g. 𝐴 = [−1 + 2𝑖 0 3 + 4𝑖 ] = −𝐴𝐻 , 𝐵 = [ ( ] = −𝐵𝐻 , 𝑒𝑡𝑐.
− 𝑐 − 𝑑𝑖 ) 𝑏
−2 + 3𝑖 −3 + 4𝑖 0
Note that:
1. In a Hermitian matrices all diagonal entries are always Real.
2. In a skew-hermitian matrices all diagonal entries are always zero.
3. If matrix A is real matrix, then 𝐴𝑇 = 𝐴𝐻 .
4. If A is any complex square matrix, then 𝐴 + 𝐴𝐻 is always Herimitian and skew –
herimitian matrices.
15. Unitary Matrix :
A square complex matrix A is said to be “Unitary Matrix”,
if 𝐴 𝐴𝐻 = 𝐼 = 𝐴𝐻 𝐴 𝑜𝑟 𝐴𝐻 = 𝐴−1 .
Note that, (1) If A and B are unitary, then 𝐴𝐻 , 𝐴−1 . and AB are also unitary.
(2) If A is complex matrix, then (𝑖) A is unitary, (ii) the rows of A forms an orthonormal
set and