On a Windows‐based computer with MATLAB^® software installed, you can double‐click on the MATLAB icon (like the one on the right side) to start MATLAB. Once MATLAB has been started, you will see the MATLAB desktop as shown in Figure I.1, which has the MATLAB Command window in the lower middle where a blinking cursor appears to the right of the MATLAB prompt ‘>>’ waiting for you to type in MATLAB commands/statements. It also contains other windows each labeled Current Folder, Editor, and Workspace (showing the contents of MATLAB memory).

How do we work with the MATLAB Command window?

• By clicking on ‘New’/‘Open’ in the groups of functionalities under HOME tab and then selecting an item in their dropdown menus, you can create/edit any file with the MATLAB editor.
• By typing any MATLAB commands/statements in the MATLAB Command Window, you can use various powerful mathematic/graphic functions of MATLAB.
• If you have an M‐file which contains a series of commands/statements for performing a target procedure, you can type in the filename (without the extension ‘.m’) to run it.
• By clicking on ‘Set Path’ in the right part of the toolstrip, you can make the MATLAB search path list include or exclude the paths containing the files you want to or not to be run.
• By typing a search term like a keyword or a function name into the Search Documentation box at the top‐right part, you can search help documentation for what you want to know about.
• To undock, i.e. separate the Editor Window from the MATLAB desktop, click on the Editor Actions button (down‐arrow‐shaped) in the top‐right part of the Editor Window and select ‘Undock’ in its drop‐down menu. To dock the Editor Window back to the desktop, click on the Editor Actions button and select ‘Dock Editor’ in its drop‐down menu.

Some of mathematical functions and special reserved constants/variables defined in MATLAB are listed in Table I.1. Table I.2 shows the graphic line specifications used in the plot( ) command.

Function	Remark	Function	Remark
cos(x)		exp(x)	Exponential function
sin(x)		log(x)	Natural logarithm
tan(x)		log10(x)	Common logarithm
acos(x)	cos−1(x)	abs(x)	Absolute value
asin(x)	sin−1(x)	angle(x)	Phase of a complex number [rad]
atan(x)	−π/2≤tan−1(x)≤π/2	sqrt(x)	Square root
atan2(y,x)	−π ≤ tan−1(y/x) ≤ π	real(x)	Real part
cosh(x)	(ex + e−x)/2	imag(x)	Imaginary part
sinh(x)	(ex − e−x)/2	conj(x)	Complex conjugate
tanh(x)	(ex − e−x)/(ex + e−x)	round(x)	The nearest integer (round‐off)
acosh(x)	cos h−1(x)	fix(x)	The nearest integer towards 0
asinh(x)	sin h−1(x)	floor(x)	The greatest integer ≤ x
atanh(x)	tan h−1(x)	ceil(x)	The smallest integer ≥ x
max	Maximum and its index	sign(x)	1(positive)/0/−1(negative)
min	Minimum and its index	mod(y,x)	Remainder of y/x
sum	Sum	rem(y,x)	Remainder of y/x
prod	Product	eval(f)	Evaluate an expression
norm	Norm	feval(f,a)	Function evaluation
sort	Sort in the ascending order	polyval	Value of a polynomial function
clock	Present time	poly	Polynomial with given roots
find	Index of element(s)	roots	Roots of polynomial
tic	Start a stopwatch timer	toc	Read the stopwatch timer (elapsed time from tic)
date	Present date
Reserved variables with special meaning
i, j		pi	π
eps	Machine epsilon	Inf, inf	Largest number(∞)
realmax,realmin	Largest/smallest positive number	NaN	Not_a_Number(undetermined)
end	The end of for loop or if, while	break	Exit while/for loop
nargin	Number of input arguments	nargout	Number of output arguments
varargin	Variable input argument list	varargout	Variable output argument list

Line type	Point type (Marker symbol)			Color
‐ solid line	.(dot)	+(plus)	*(asterisk)	r: red	m: magenta
: dotted line	^: Δ	>: >	o(circle)	g: green	y: yellow
‐‐ dashed line	p:	v: ∇	x: x‐mark	b: blue	c: cyan(sky blue)
‐. dash‐dot	d: ⋄	<: <	s: □	k: black