1. ECE 1304 Introduction to Electrical and Computer Engineering
Section 1.4
Operators and Functions 1

2. Commands and Operators
Description
clc
Clears the Command Window
clear
Clears all variables from memory
clear var1
Clears var1 from memory
exist(‘name’)
Determines if a file or variable exists with the name ‘name’.
quit
Stops MATLAB
who
Lists the variables currently in memory
whos
Lists the variables currently in memory and indicates their size and if they are complex

3. Commands and Operators
Description +
Plus; addition operator -
Minus, subtraction operation *
Scalar and matrix multiplication operator .*
Array (point-by-point) multiplication operator ^
Scalar and matrix exponentiation operator .^
Array (point-by-point) exponentiation operator \
Left division operator /
Right division operator .\
Array (point-by-point) Left division operator ./
Array (point-by-point) Right division operator :
Colon; generates regularly spaced elements ()
Parentheses; encloses function arguments and array indices; overrides precedence

4. Commands and Operators
Description []
Brackets; encloses array elements {}
Braces; encloses cell elements .
Decimal point
...
Ellipsis; continues a line ,
Comma; separates elements in an array ;
Semicolon; suppresses screen printing, denotes a new row in an array %
Percent sign; designates a comment and specifies formatting '
Quote sign and transpose operator .'
Nonconjugated transpose operator =
Assignment operator

5. Special Variables and Constants
Symbol
Description
ans
Temporary variable containing the most recent answer.
eps
Accuracy of floating point calculations
i, j
Imaginary unit value; sqrt(-1)
Inf
Infinity
NaN
Not a number; occurs when an operation is undefined pi
The number …

6. Mathematical Functions
exp(x) – Exponentiation

7. Mathematical Functions
sqrt(x) – Square Root

8. Mathematical Functions
log(x) – Natural Logarithm

9. Mathematical Functions
log10(x) – Base 10 Logarithm

10. Mathematical Functions
abs(x) – Absolute Value

11. Mathematical Functions
angle(x) – Phase Angle

12. Mathematical Functions
conj(x) – Complex Conjugate

13. Mathematical Functions
imag(x) – Imaginary Part

14. Mathematical Functions
real(x) – Real Part

15. Mathematical Functions
ceil(x) – Round toward + Inifinity

16. Mathematical Functions
fix(x) – Round toward Zero

17. Mathematical Functions
floor(x) – Round toward Negative Infinity

18. Mathematical Functions
round(x) – Round to nearest integer

19. Mathematical Functions
sign(x) – Return algebraic sign

20. Trigonometric Functions
All angles must be in radians
angle_in_Radians = angle_in_Degrees*pi/180
cos(x)
sec(x)
sin(x)
csc(x)
tan(x)
cot(x)

21. Inverse Trigonometric Functions
All angles are returned in radians
acos(x)
asec(x)
asin(x)
acsc(x)
atan(x)
acot(x)
atan2(y,x) Four quadrant inverse tangent. x and y are the coordinates of a point.

22. Trigonometric Functions
All angles must be in degrees
angle_in_Degrees = angle_in_Radians*180/pi
cosd(x)
secd(x)
sind(x)
cscd(x)
tand(x)
cotd(x)

23. Inverse Trigonometric Functions
All angles are returned in degrees
acosd(x)
asecd(x)
asind(x)
acscd(x)
atand(x)
acotd(x)
atan2d(y,x) Four quadrant inverse tangent. x and y are the coordinates of a point.