Post on 14-Dec-2015
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What is MATLABWhat is MATLAB
A computer program for doing numerical computation including; Arithmetic, Polynomials, Graphics, 2-D Plots, Matrices, Systems of Equations etc.
Open ProgramOpen Program Click “MATLAB R2006a” on Desktop
OR
Go to “Start” All Program > MATLAB > MATLAB R2006a
MATLAB DesktopMATLAB Desktop Default layout Arranging the
Desktop including resizing, moving, and closing tools.
Arithmetic CalculatorArithmetic Calculator >> 1+1
ans =
2
>> (7*5)+2
ans =
37
>> [(8+2^2)/(1*3)]
ans =
4
Type in any basic arithmetic as shown
Click “Enter”
Basic OperationsBasic Operations Operation MATLAB
x + y x+y
x - y x-y
x y x*y
x / y x/y
xy x^y
ex exp(x)
| x | abs(x)
π pi
sqrt(x)
VectorsVectors To enter a vector >> v = [1 2 3]
v = 1 2 3
To transpose a column vector to a row vector, use an apostrophe “‘“
>>v = [1 2 3]’
v = 1
2
3
To increment using colon
>> v = [1:5]v = 1 2 3 4 5
To increment other than1
>>v = [5:0.5:7]v = 5 5.5 6 6.5 7
To view individual entries in this vector
v(2)Ans = 5.5
Vector ExamplesVector Examples
>> v = [1:5]; >> u = [0:-1:4]; u+v Ans: 1 1 1 1 1 v^2 Ans: 1 4 9 16 25
Note: Error message will appear from adding two vectors whose dimensions are different.
Matrix ExamplesMatrix Examples
>> a = [ 1 2; 3 4 ]; >> b = [ 0 1; 2 3 ]; >> a+b ans = 1 3 5 7 >>a*b ans = 4 7 8 15
T = a+b; >> inv(t) ans =
-0.8750 0.3750
0.6250 -0.1250 >> inv(t)/t ans =
1.0000 -0.3750
-0.6250 0.2500
PlottingPlotting
Use “plot” command
Format: plot(x,y, ‘m’)
The third input is a characteristic of the graph.
y yellow
m magenta
c cyan
r red
g green
b blue
k black
* star
. dotted
-- dashed
x x-mark
Plotting ExamplesPlotting Examples
x = 0:0.1:100; y = 2*x; plot (x,y,'--')
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Plotting Examples Plotting Examples 22
x = 0:0.1:5; y = sin (x); plot (x,y,'x')
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Plotting Examples Plotting Examples 33
x = linspace(0,2*pi,50); y = sin (x); z = cos (x); plot (x,y, x,z)
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Sub-PlottingSub-Plotting
Use “subplot” command to put more than one plot in the same figure
subplot (m,n,p)
where; m = number of rows
n = number of column
p = plot number
Sub-Plotting ExampleSub-Plotting Example
x = linspace(0,2*pi,50);
y = sin (x); z = cos (x); subplot (1,2,1) plot (x,y) subplot (1,2,2) plot (x,z)
0 2 4 6 8-1
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Adding TextAdding Text
Below are the text adding related commands
title (‘title name’)
xlabel (‘label of the x-axis’)
ylabel (‘label of the y-axis’)
gtext (‘put text in the middle of plot’)
Adding Text ExampleAdding Text Example
x = 0:0.1:100; y = 2*x; plot (x,y,'--') title ('title name') xlabel ('label of the x-axis') ylabel ('label of the y-axis') gtext ('put text in the middle of plot')
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label of the x-axis
labe
l of
the
y-ax
is
put text in the middle of plot
PolynomialsPolynomials Vector is used to
represented polynomial
in MATLAB.
For example;
t3+4t2-3t+1
t = [1 4 -3 1]
orx5+3x2-6x = [1 0 0 3 0 -6]
Polynomial ExamplesPolynomial Examples To multiply two
polynomial
x = [1 2 3];
y = [2 4 6 8];
z = conv(x,y)
z =
2 8 20 32 34 24
To devide two polynomial
[xx, w] = deconv(z,y) xx =
1 2 3 w =0 0 0 0 0 0
Symbolic MathSymbolic Math
Use for factoring solving, root finding, differentiating, and integrating.
Use sym command to create a symbolic object.
Example:sqrt(2)ans
1.4142
With sym commanda = sqrt(sym(2))ans
a = 2^(1/2)
Symbolic MathSymbolic Math Cont. Cont.
Use double command to get the value of the symbolic object.
double(a)
ans =
1.4142
Use sym command to find common denominator.
sym(2)/sym(5) + sym(1)/sym(3)
ans =
11/15
Solve Command ExampleSolve Command Example
Eqn = ax^2 + bx + c = 0 To solve symbolically for the variable x use
solve(Eqn,'x') To find the value of b which makes this true
solve(QuadEqn,'a=3','c=-1','x=-1') A more complicated example
solve(QuadEqn,'a=sqrt(c)','b=2','x=-1')