BASIC MATLAB TUTORIAL : PART 1

Matlab is a robust software. We can perform a lot of numerical operations on it. This blog series is just for the beginners. Its an introductory series so only the basic operations will be considered.

NOTE: Things written after ” >> “ this symbols are the the codes written in the MATLAB command window & the things written after ” = “ are the output of the MATLAB codes.

  1. Can MATLAB be used as a calculator ?The answer to this question is Yes, but it will be a very expensive calculator. We can perform all the mathematical operations in it directly.>> (1+2-3*(6+5))/2
    ans =
    -15>> 1-2+3*(4/5)
    ans =
    1.4000

    >> sin(30)^2 + cos(30)^2

    ans =

    1

    >> tan(45)+cot(45)

    ans =

    2.2371

    i and j represents the same complex parameter:

    >> (1+2i)+(3+4i)

    ans =

    4.0000 + 6.0000i

    >> (1+2j)+(3+4j)

    ans =

    4.0000 + 6.0000i

  2. Difference between “format long” and “format short”: To get upto 15 decimal place of a value we will use “format long” before the operation.>> format long
    >> 22/7
    ans =
    3.142857142857143″format short” is used to get upto 4 decimal place.

    >> format short
    >> 22/7
    ans =
    3.1429

  3. How to write matrix in the MATLAB ? Matrix is the basic building block of the entire operation of MATLAB so this point is very important . See the difference : the matrix are written in [ row*column ] format
    (a) Its a 1*1 matrix having the element 1234
    >> A=[1234]
    A =
    1234(b) Its a 1*4 row matrix having the 4 element as  1 , 2 , 3, 4
    >> B=[1 2 3 4]
    B =

    1     2     3     4

    (c) Its a 4*1 column matrix having the 4 element as  1 , 2 , 3, 4

    >> C=[1;2;3;4]

    C =

    1
    2
    3
    4

    (d) Its a 2*2 Square matrix having the 4 element as  1 , 2 , 3, 4. The ” ; ” symbol generates the row and the ” ” space key generates the column.

    >> X=[1 2;3 4]

    X =

    1     2
    3    4

    (e) a 2*3 matrix

    >> y=[1 2 3;4 5 6]

    y =

    1    2    3
    4   5    6

  4. How to create a constant and change the value of the matrix: Let us assume the symbol ” k ” is a variable representing constant. I want to modify my Matrix x as shown below:NOTE: The text written in GREEN COLOUR are the comment statements. They are Not compiled or run in the MATLAB operations. They are used just to make the user understand the program properly. Its a very good practice to write comments as often as possible..>> x=[1 2;3 4] % My matrix
    x =
    1     2
    3    4>> k=10 % My constant value

    k =

    10

    >> x_modify_1=k*X % Matrix multiplied by k

    x_modify_1 =

    10     20
    30    40

    >> x_modify_2=X./k % Matrix divided by k

    x_modify_2 =

    0.1000     0.2000
    0.3000    0.4000

    Note a point that i have use ” ./ ” for division and not the usual ” / ” symbol because matrix division is an element to element operation and must be performed for all the elements.

  5. How to find transpose of a Matrix ?>> a=[11    12    13;14    15    16;17    18    19]a =
    11     12     13
    14    15    16
    17    18    19

    >> a_transpose=a’         %” a_transpose ” is just a variable name given to the transpose

    a_transpose =

    11     14     17
    12    15    18
    13    16    19

    ” ‘ ” this symbol will perform the transpose of the matrix.There is an alternate way of performing transpose and that is by using the standard build in function called ” transpose( )”.

    >> a_transpose_alternate=transpose(a)  %alternate way of transposing

    a_transpose_alternate =

    11     14     17
    12    15    18
    13    16    19

  6. How to display a statement/value in MATLAB? For this we will take the help of the in-build function present in MATLAB which is ” disp(‘ your statement‘) ” . Lets see an example to display a statement:>> disp(‘Hi.. My Name is MOUSAM CHOUDHURY’)
    Hi.. My Name is MOUSAM CHOUDHURYWe can also display values with this function:

    >> a=[12 13]

    a =12     13

    >> disp(a)
    12     13

    >> sum=7+8;    %  ” ; “ symbol after a command prevents the result from displaying

    >> disp(sum)
    15

    another example:

    >> x=’Thank you for watching my website:http://ilearn2share.com/’ ;
    >> disp(x)
    Thank you for watching my website:http://ilearn2share.com/

    Part 2 of this Basic MATLAB tutorial series will be uploaded soon.

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