Introduction to MATLAB

When you start MATLAB, the desktop appears in its default layout.

      

Table 1: Basic Arithmetic Operations

Sl. No.	Input	Output	Sl. No.	Input	Output
1	2+3	5	5	x^2	25
2	x=5; y=3; x+y	8	6	sqrt(y)	1.7321
3	x*y	15	7	x/0	Inf
4	x/y	1.6667	8	(x+y)/(x^2+y^2)	0.2353

 

Table 2: Basic Functions

Sl. No.	Input	Output	Sl. No.	Input	Output
1	x=2; y=pi;		8	nthroot(-4,3)	-1.5874
2	sin(y/4) asin(0.7071)	0.7071 0.7854	9	nthroot(-4,2)	Error: Error using nthroot If X is negative, N must be an odd integer.
	asin(x)= inverse sine	Output will be displayed in terms of radians		Syntax nthroot(X,N)
3	exp(x)	7.3891	10	z=sqrt(-4)	0.0000 + 2.0000i
4	log(x)	0.6931	11	imag(z)	2
5	z=log10(x)	z=0.3010	12	real(z)	0
6	format long z	z = 0.301029995663981	13	abs(z)	2
7	format short cosh(y)	11.5920	14	abs(-4)	4

# Note: If you end a statement with a semicolon, MATLAB performs the computation, but suppresses the display of output in the Command Window.

Table 3: Basic Commands

Sl. No.	Command	Output
1	clc	Clears all the text from the Command Window, resulting in a clear screen. (Does not delete the variables created)
2	clear	Removes all variables from the current workspace, releasing them from system memory. (Does not clear the screen)
3	close all	Closes all figures whose handles are visible
4	syms	creates symbolic scalar variables Example Input Output sin(x) Error: Unrecognized function or variable 'x'. syms x y sin(x)+exp(y) sin(x)+exp(y)
5	vpa	Variable-precision arithmetic  evaluate each element of the symbolic input x to at least d significant digits Input Output a=((1 + sqrt(sym(5)))/2) a=5^(1/2)/2 + 1/2 vpa(a) 1.6180339887498948482045868343656 vpa(a,3) 1.62
6	simplify	Performs algebraic simplification Input Output syms x sin(x)^2+cos(x)^2 cos(x)^2 + sin(x)^2 simplify(cos(x)^2 + sin(x)^2) 1
7	pretty	Prints expression in a plain-text format that resembles typeset mathematics. Input Output syms x y z=(y^2 + x^2)/(x*y) z=(y^2 + x^2)/(x*y) pretty(z)   2     2 y + x ------- x y *For true typeset rendering, use Live Scripts instead
8	subs	subs(s, old, new) returns a copy of s, replacing all occurrences of old with new, and then evaluates s. Input Output syms x y subs(x + y,x,4) 4+y f(x,y) = x + y; f = subs(f,[x,y],[a,b]) b + a
9	input	input(prompt) displays the text in prompt and waits for the user to input a value and press the Return key. Input Output x=input( Enter the value of x: ) Enter the value of x: _
10	fprintf	Formats data and displays the results on the screen Input Output a=1; b=1.45; f=x+y; fprintf( a=%d, b=%f, f=%s , a,b,f) a=1, b=1.450000, f=x + y To format numeric and character data use the following %d - Integer, %f - Floating-point, %s - String To format the display use the following \t - tab space, \n - next line
11	disp	Disp(x) displays the value of variable x without printing the variable name Input Output a=1 disp(a) disp( a is equal to + a) a=1 1 a is equal to 1
12	diff(f,var,n)	Differentiate the given function n times with respect to variable var Input Output syms f(x) f(x)=sin(x); diff(f)   cos(x) syms f(x) f(x)=sin(x); diff(f,x) cos(x) syms f(x) f(x)=sin(x); diff(f,x,2) -sin(x)
13	int(f,var,a,b)	Evaluate the definite integral of the function f from a to b Input Output syms f(x) f(x)=sin(x); int(f)   -cos(x) syms f(x) f(x)=csc(x); int(f,x) log(tan(x/2))   *csc(x)=cosec(x) syms f(x) f(x)=sin(x); int(f,x,0,pi/2)   1

 

Table 4: Vectors and Matrices

Sl. No.	Input	Output
1	x=[1,2,3,4,5,6]	x = 1 2 3 4 5 6
2	x=1:1:6	x = 1 2 3 4 5 6
3	x=1:6	x = 1 2 3 4 5 6
4	x=linspace(1,6,5)	x = 1.0000 2.2500 3.5000 4.7500 6.0000
5	y=x+1	y = 2.0000 3.2500 4.5000 5.7500 7.0000
6	y=x*2	y = 2.0000 4.5000 7.0000 9.5000 12.0000
7	a=[1,2,3,2,1]   z=a*x	a = 2 2 2 2 2 Error: Incorrect dimensions for matrix multiplication. Check that the number of columns in the first matrix matches the number of rows in the second matrix. To operate on each element of the matrix individually, use TIMES (.*) for elementwise multiplication. a and x are 1x5 matrices hence multiplication is not possible
8	z=a.*x	z = 1.0000 4.5000 10.5000 9.5000 6.0000 ( .* represents elementwise multiplication, i.e., it will take z = 1*1 2*2.25 3*3.5 2*4.75 1*6 )
9	y=x/2	y = 0.5000 1.1250 1.7500 2.3750 3.0000
10	y=2/x	Error: Matrix dimensions must agree. (The number 2 will be interpreted as a 1x1 matrix, making regular division unfeasible. Use element-wise division instead.)
11	y=2./x	y = 2.0000 0.8889 0.5714 0.4211 0.3333
12	y=a./x	y = 1.0000 0.8889 0.8571 0.4211 0.1667
13	length(x)	6
14	M=[1 2 3;3 4 5;6 7 8]	1 2 3 3 4 5 6 7 8	15	N=[1 3 5;-1 4 6;-3 4 -2]	1 3 5 -1 4 6 -3 4 -2
16	M+N	2 5 8 2 8 11 3 11 6	17	M*N	-10 23 11 -16 45 29 -25 78 56
18	b=ones(1,3)	1 1 1	19	x=zeros(3,4)	0 0 0 0 0 0 0 0 0 0 0 0
20	x*b	Incorrect dimensions for matrix multiplication. x is a 3x4 matrix and b is a 1x3 matrix hence multiplication is not possible
21	b*x	0 0 0 0	22	2*b.*N	2 6 10 -2 8 12 -6 8 -4
22	size(x)	3 4	23	det(N)	-52
24	inv(N)	0.6154 -0.5000 0.0385 0.3846 -0.2500 0.2115 -0.1538 0.2500 -0.1346

Working with Script file (.m file)

<SScripts consist of sets of MATLAB commands that are kept in basic text files.

<]>Script files must end with the extension '.m' (for example 'myScript.m'), and often these files are referred to as m-files.

<>> Essentially, m-files run a sequence of MATLAB instructions. Alternatively, they can serve as functions capable of receiving inputs, generating multiple outputs.

Working with Live Script file (.mlx file)

<!>Live scripts and live functions are interactive documents that combine MATLAB code with formatted text, equations, and images in a single environment called the Live Editor. In addition, live scripts store and display output alongside the code that creates it.

<!>To create a live script: MATLAB>Home>Live Script