1. Introduction to MATLAB Plotting LAB 3

2. Basic Task: Plot the function sin(x) between 0≤x≤4π
Create an x-array of 100 samples between 0 and 4π.
Calculate sin(.) of the x-array
Plot the y-array
>>x=linspace(0,4*pi,100);
>>y=sin(x);
>>plot(y)

3. Plot the function e-x/3sin(x) between 0≤x≤4π
Create an x-array of 100 samples between 0 and 4π.
Calculate sin(.) of the x-array
Calculate e-x/3 of the x-array
Multiply the arrays y and y1
>>x=linspace(0,4*pi,100);
>>y=sin(x);
>>y1=exp(-x/3);
>>y2=y*y1;

4. Plot the function e-x/3sin(x) between 0≤x≤4π
Multiply the arrays y and y1 correctly
Plot the y2-array
>>y2=y.*y1;
>>plot(y2)

5. Display Facilities plot(.) stem(.) Example:
>>x=linspace(0,4*pi,100);
>>y=sin(x);
>>plot(y)
>>plot(x,y)
Example:
>>stem(y)
>>stem(x,y)

6. Display Facilities title(.) xlabel(.) ylabel(.)
>>title(‘This is the sinus function’)
>>xlabel(‘x (secs)’)
>>ylabel(‘sin(x)’)

7. Plot Properties
title
legend
ylabel
xlabel

8. plot(x,y) x=[1 2 3 5 7 7.5 8 10]; y=[2 6.5 7 7 5.5 4 6 8]; plot(x,y)
Plot function
plot(x,y)
where the variables x and y are vector and must be of same size i.e the number of elements should be equal.
x=[ ];
y=[ ];
plot(x,y)

9. plot(x,y,‘line specifiers’,‘PropertyName’,PropertyValue)
Plot function
plot(x,y,‘line specifiers’,‘PropertyName’,PropertyValue)
Line specifiers
Line specifiers are optional and can be used to define the style and color of the
line and the type of markers (if markers are desired).
solid (default)
dashed
dotted
dash-dot
Line Style
Specifier - -- : -.
red
green
blue
cyan
Line color
Specifier r g b c
magenta
yellow
black
white
Line color
Specifier m y k w

10. plot(x,y,‘line specifiers’,‘PropertyName’,PropertyValue)
Plot function
plot(x,y,‘line specifiers’,‘PropertyName’,PropertyValue)
Line specifiers
Line specifiers are optional and can be used to define the style and color of the
line and the type of markers (if markers are desired).
plus sign
circle
asterisk
point
cross
triangle (pointed up)
triangle (pointed down)
Marker type
Specifier + o * . × ^ v
square
diamond
five pointed star
six pointed star
triangle (pointed left)
triangle (pointed right)
Marker type
Specifier s d p h
<
>

11. Stem plot figure X = linspace(0,2*pi,50)'; Y = [cos(X), 0.5*sin(X)];
stem(Y)

12. Subplots x = linspace(0,10); y1 = sin(x); y2 = sin(2*x);
figure
subplot(2,2,1)
plot(x,y1)
title('Subplot 1: sin(x)')
subplot(2,2,2)
plot(x,y2)
title('Subplot 2: sin(2x)')
subplot(2,2,3)
plot(x,y3)
title('Subplot 3: sin(4x)')
subplot(2,2,4)
plot(x,y4)
title('Subplot 4: sin(8x)')

13. Example: dual y-axis

14. Polar Plot theta = 0:0.01:2*pi; rho = sin(2*theta).*cos(2*theta);
figure
polar(theta,rho,'--r')

15. Plot Matrix: comparison b/w datasets
X = randn(50,3);
plotmatrix(X,'*r')

16. 3D Shaded surface plot: SURF
[X,Y,Z] = peaks(25);
figure
surf(X,Y,Z);
Sphere with two colors

17. MESH Plot [X,Y] = meshgrid(-8:.5:8); R = sqrt(X.^2 + Y.^2) + eps;
Z = sin(R)./R;
figure
mesh(Z)