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

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

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

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

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 3.14159…

Mathematical Functions exp(x) – Exponentiation

Mathematical Functions sqrt(x) – Square Root

Mathematical Functions log(x) – Natural Logarithm

Mathematical Functions log10(x) – Base 10 Logarithm

Mathematical Functions abs(x) – Absolute Value

Mathematical Functions angle(x) – Phase Angle

Mathematical Functions conj(x) – Complex Conjugate

Mathematical Functions imag(x) – Imaginary Part

Mathematical Functions real(x) – Real Part

Mathematical Functions ceil(x) – Round toward + Inifinity

Mathematical Functions fix(x) – Round toward Zero

Mathematical Functions floor(x) – Round toward Negative Infinity

Mathematical Functions round(x) – Round to nearest integer

Mathematical Functions sign(x) – Return algebraic sign

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)

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.

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)

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.