MATLAB: First time user of Matlab having issues trying to plot: y=sin x/x on an interval -30

homeworknjitass1

Below is the code below I created and when I enter it at the >> prompt in the Command window, nothing happens and no graph appears.

x=linespace(-30,30,10001);
y=sin(x)./x;
plot(x,y,'-');
axis([-30 30-1 1])
xlabel('x')
ylabel('y')
title('Fred Smith')

1-is the code correct and do I need to create an m-file ->enter the code then save -> then type in the file name at the >> prompt for it to run. I know this is very basic but I was given the assignment without ever using Matlab and I have been researching this for hours. Thanks

Best Answer

Use

 x = linspace(-30,30,10001);

and

 axis([-30 30 -1 1])

instead. Otherwise the code looks fine. That is, copy-paste the whole thing and execute in the MATLAB command window. Alternatively, you can put the code into a script or a function and follow the steps you outlined above.

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MATLAB: How to fix the code so that the x and y equations run

If y is not allowed to go negative, alter my other solution and use clipping to zero. Note how the farthest distance it goes is when the angle is at 45 degrees, which makes intuitive sense.

% Initialization / clean-up code.
clc;    % Clear the command window.
close all;  % Close all figures (except those of imtool.)
clear;  % Erase all existing variables. Or clearvars if you want.
workspace;  % Make sure the workspace panel is showing.
format short g;
format compact;
fontSize = 20;
g = 9.81;
v0 = 5;
t = 0 : (1/128) : 3;
for theta0 = 15:15:75
  x = v0 .* cosd(theta0) .* t;
  y = v0 .* sind(theta0) .* t - (0.5 * g * t.^2);
  % Don't let y go negative:
  y = max(y, 0);
  plot(x, y, '-', 'LineWidth', 2);
  hold on;
end
grid on;
xlim([0,3]);
% Draw x axis:
line(xlim, [0,0], 'Color', 'k', 'LineWidth', 2);
legend('15', '30', '45', '60', '75');
title('Y vs. X', 'FontSize', fontSize);
xlabel('X', 'FontSize', fontSize);
ylabel('Y', 'FontSize', fontSize);
% Set up figure properties:
% Enlarge figure to full screen.
set(gcf, 'Units', 'Normalized', 'OuterPosition', [0 0 1 1]);
% Get rid of tool bar and pulldown menus that are along top of figure.
set(gcf, 'Toolbar', 'none', 'Menu', 'none');
% Give a name to the title bar.
set(gcf, 'Name', 'Demo by ImageAnalyst', 'NumberTitle', 'Off')

MATLAB: How to plot complex signal

Try this

clc;    % Clear the command window.
close all;  % Close all figures (except those of imtool.)
clear;  % Erase all existing variables. Or clearvars if you want.
workspace;  % Make sure the workspace panel is showing.
format long g;
format compact;
fontSize = 20;
t = linspace(0, 2*pi, 90);
j = sqrt(-1);
complexSignal = cos(t) + j*sin (t)
% Get the real component and plot it on the x axis
x = real(complexSignal);
y = imag(complexSignal);
plot(x, y, 'bo-', 'LineWidth', 2);
grid on;
title('Plot of cos(t) + j*sin (t)', 'Fontsize', fontSize);
xlabel('Real Component', 'Fontsize', fontSize);
ylabel('Imaginary Component', 'Fontsize', fontSize);
axis square;
% Enlarge figure to full screen.
set(gcf, 'Units', 'Normalized', 'OuterPosition', [0 0 1 1]);

Best Answer

Related Solutions

MATLAB: How to fix the code so that the x and y equations run

MATLAB: How to plot complex signal

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