Question

please help me with this MATLAB CODE and explain to me what each line does and what is used for? leave your comments as words, not as pictures.

clear all; close all; For a script file, you better start with clear all and close all However, for a fucntion, you better NOT to start with them $$ End of cell mode example $$ Plot function t = 0:0.1:5; x1 = sin(2*5*5); x2 = cos (3*7*t) figure (1) subplot (311),plot(t, xl, 'r-o'), hold on; subplot 1311), plot(t,x2, 'k:'), hold off; title('Lab #4'); subplot (312 L.plot(t, x1, 'Linewidth',10), hold on; subplot (312), plot(t, x2, 'Linewidth',3), hold off; grid on: subplot (313.plot(t, x1,'c-3',t,x2, 'm:>'); xlabell'time [sec]'); wlabel('values'); legend('xl', '2' * End of plot function $$ 3D plotting t = 0:2*pi/100:15*pi; x1 = sin(t); x2 = cos(thi figure (2) plot3 (x1,x2,t,'*', 'Linewidth', 2); axis off; fiqure (3) plot3(x1,x2,t,'rt', 'Linewidth', 2); axis on; grid on; Xabel('xl'); slaked ('2'), slabedi't'u title( 'A helix example in Plot3 Help file'); legend('line'); 3 End of 3D plotting $$ File I/O function, "save" clear all; close all; else x = [1 2 3; 4 5 6; 7 8 912 y = 0:2:10; z = 1:3:15; save ('mywariables', 'nanz'); $check your directory what file is made. $$ End of File I/O function, "save" $$ File I/O function, "load" clear all; sis; At this point, there is no variable in your workplace MXSTR = 'ENGR320 labs whos load('usvariabtemat whosCheck what variables are loaded in your work place!! $$ End of File I/O function, "load"

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clear all; close all; % For a script file, you better start with clear all and close all

                       % However, for a fucntion, you better NOT to start

                       % with them

%% End of cell mode example

%% Plot function

t = 0:0.1:5;

x1 = sin(2*5*t); x2 = cos(3*7*t);

figure(1)

subplot(311),plot(t,x1,'r-o'),hold on;

subplot(311),plot(t,x2, 'k:^'),hold off;

title('Lab #4');

subplot(312),plot(t,x1,'Linewidth',10),hold on;

subplot(312),plot(t,x2,'Linewidth',3),hold off;

grid on;

subplot(313),plot(t,x1,'c-s',t,x2,'m:>');

xlabel('time [sec]'); ylabel('values');

legend('x1','x2');

%% End of Plot function

%% 3D plotting

t = 0:2*pi/100:15*pi;

x1 = sin(t); x2 = cos(t);

figure(2)

plot3(x1,x2,t,'r*','Linewidth',2); axis off;

figure(3)

plot3(x1,x2,t,'r*','Linewidth',2); axis on; grid on;

xlabel('x1'); ylabel('x2'), zlabel('t');

title('A helix example in Plot3 Help file'); legend('line');

%% End of 3D plotting

%% File I/O function, "save"

clear all; close all; clc;

x = [1 2 3; 4 5 6; 7 8 9];

y = 0:2:10; z = 1:3:15;

save('myvariables','x','y','z'); %check your directory what file is made.

%% End of File I/O function, "save"

%% File I/O function, "load"

clear all; clc; %At this point, there is no variable in your workplace

MySTR = 'ENGR320 labs';

whos

load('myvariables.mat');

whos %Check what variables are loaded in your work place!!

%% End of File I/O function, "load"

Answer 1

clear all; close all; % For a script file, you better start with clear all and close all

                       % However, for a fucntion, you better NOT to start

                       % with them

%% End of cell mode example

%% Plot function

%%Initializing time axis from 0 to 5 with stepping of 0.1

t = 0:0.1:5;

%%x1 and x2 are the two target variables based on value of t given to it in sine and cosine functions

x1 = sin(2*5*t); x2 = cos(3*7*t);

%initializes the first figure for the output plot

figure(1)

%%[should be subplot(3,1,1)] It will be the first plot of a 3X1 grid output,hold on retains plots in the current axes so that new plots added to the axes do not delete existing plots

subplot(311),plot(t,x1,'r-o'),hold on;

%%[should be subplot(3,1,1)] It will make a plot on the first row in a single column, hold off sets the hold state to off so that new plots added to the axes clear existing plots and reset all axes properties

subplot(311),plot(t,x2, 'k:^'),hold off;

%% Label for the plot is 'Lab4' at the top of the first plot

title('Lab #4');

%%[should be subplot(3,1,2)] It will be the second plot of a 3X1 grid output, just below the previous plot,hold on retains plots in the current axes so that new plots added to the axes do not delete existing plots

subplot(312),plot(t,x1,'Linewidth',10),hold on;

%%[should be subplot(3,1,2)] It will make a plot on the first row in a single column, hold off sets the hold state to off so that new plots added to the axes clear existing plots and reset all axes properties

subplot(312),plot(t,x2,'Linewidth',3),hold off;

%%grid on displays the major grid lines for the current axes or chart returned by the gca(get current axis) command. Major grid lines extend from each tick mark.

grid on;

subplot(313),plot(t,x1,'c-s',t,x2,'m:>');

%%puts labels of the plot, i.e., on the x axis as 'time[sec]' and y axis as 'values'

xlabel('time [sec]'); ylabel('values');

%%legend creates a legend with descriptive labels for each plotted data series i.e., x1 and x2

legend('x1','x2');

%% End of Plot function

%% 3D plotting

%% used to calculate time

t = 0:2*pi/100:15*pi;

%%x1 and x2 are the two target variables based on value of t given to it in sine and cosine functions

x1 = sin(t); x2 = cos(t);

%initializes the second figure for the output plot

figure(2)

%%plots the only plot in the figure 3, here "axis off" is used

plot3(x1,x2,t,'r*','Linewidth',2); axis off;

%%initializes the first figure for the output plot

figure(3)

%%plots the only plot in the figure 3, here "grid on" is used as describe in a previous comment and "axis on"

plot3(x1,x2,t,'r*','Linewidth',2); axis on; grid on;

%%puts labels of the plot, i.e., on the x axis as 'x1' and y axis as 'x2', z axis as 't' for the 3D plot

xlabel('x1'); ylabel('x2'), zlabel('t');

%%title for the plot3 and the legent for the plot is set as 'line' for reference

title('A helix example in Plot3 Help file'); legend('line');

%% End of 3D plotting

%% File I/O function, "save"

clear all; close all; clc;

%%x,y,z are inputs from the user, X is a 3X3 array, y is a 0 to 10 range with a stepping of 2, z is a range of 1 to 15 with a stepping of 3

x = [1 2 3; 4 5 6; 7 8 9];

y = 0:2:10; z = 1:3:15;

%%this used to store the input data in the variables

save('myvariables','x','y','z'); %check your directory what file is made.

%% End of File I/O function, "save"

%% File I/O function, "load"

clear all; clc; %At this point, there is no variable in your workplace

%%a variable in which string 'ENGR320 labs' is stored

MySTR = 'ENGR320 labs';

whos

%%used to load the matlab file 'myvariables.mat'

load('myvariables.mat');

whos %Check what variables are loaded in your work place!!

%% End of File I/O function, "load"