1. Introduction to MATLAB
MATLAB is a mathematics program that works by either typing in commands or by writing programs
Typing x=5*sqrt(83)/(5^3+exp(.2)) will result in x = .3609
MATLAB handles matrix mathematics and complex number arithmetic with ease
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IntroMatlab.ppt

2. Matlab’s Workspace
Each command or each program creates a set of variables with values in the workspace
Values are kept until you no longer need them
Use clear to wipe the workspace clean
Use clear x to eliminate the variable x
Use clear variables to clear all variables
Clear the screen of text by using clc on the command line or choosing Clear Session under Edit in the menu. This does not clear the variables.
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IntroMatlab.ppt

3. Matlab’s Workspace You can check your variables at any time
who generates a listing of all variables
whos generates a listing of all variables plus the size, bytes and class of the variables
Choosing Show Workspace under the File menu brings up a window showing the same information as whos)
Type help who for more detailed information
Type the variable to see its value(s)
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IntroMatlab.ppt

4. Matlab Built-In Functions
Matlab commands and functions are broken down into many categories
Type help elfun
trigonometric functions
exponential functions
complex number functions
rounding/remainder functions
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IntroMatlab.ppt

5. Common Math Functions Trigonometric – cos, sin, tan, atan
Be sure to use radians in the argument
Square root – sqrt(2) yields 1.414
Natural Log – log(3) yields
Base 10 Log – log10(4) yields .6021
Base 2 Log – log2(4) yields 2
Exponential – exp(2) yields e2 =
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IntroMatlab.ppt

6. Complex Number Functions
Enter in rectangular form
x=4+3j or x=4+3i or x=complex(4,3)
Magnitude – abs(x) yields 5
Phase angle – angle(x) yields radians
Complex conjugate – conj(x) yields 4-3j
Real part – real(x) yields 4
Imaginary part – imag(x) yields 3
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IntroMatlab.ppt

7. Matlab – Matrix Math Matrices are rectangular arrays of numbers
Matlab uses matrix math to simplify many calculations
Each element in a matrix can be accessed using its row and column – m(row,column)
An entire row or column can be accessed to form a vector – m( : ,column) or m(row, : )
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IntroMatlab.ppt

8. Generating a Vector Generate a vector by listing its values
Rowvector=[ ]
Columnvector=[1;2;3;4;5;6;7;8;9] – the semicolon starts a new row
Create a row vector with a constant interval
T=start value : increment : end value
T=0 : 2 : 10 gives T=[ ]
T=linspace(start value, end value, number wanted)
T=linspace(0,10,5) gives T=[ ]
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IntroMatlab.ppt

9. Generating a Vector
You can create a row vector with logarithmic spacing
T=logspace(starting power of 10, ending power of 10, number of values wanted)
T=logspace(0,2,4) gives
T=[ ]
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IntroMatlab.ppt

10. Generating a Matrix
You can create a matrix by entering each row with semicolons between each row
A = [3 4 –7 ; 5 –7 3 ; –6]
A = 5 –7 3
2 0 –6
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IntroMatlab.ppt

11. Matrices and Sets of Equations
Matrices can be used to represent a system of equations and solve it
3x+4y-7z=10
5x-7y+3z=-6
2x-6z=6
The matrix equation implements the above system x
5 – y = or A * S = C
2 0 – z
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IntroMatlab.ppt

12. Matlab Solution of A*S=C
Premultiply both sides by the inverse of A
inv(A) * A * S = inv(A) * C
Which simplifies to: S = inv(A) * C
or x = .3140
Results in S = or y = .6977
or z =
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IntroMatlab.ppt

13. Running Matlab Programs
Under file, select open
Find the M-file that you want to run
The M-file should appear in the editor window
Modify the M-file as needed
Under debug, choose run
Results should be displayed in the main window
Plots should be displayed in new figure windows
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IntroMatlab.ppt