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

error

g=9.81
v0=5
theta0=15:15:75
t=0:(1/128):3
x=v0.*cosd(theta0).*t
y=v0.*sind(theta0).*t-(0.5.*g.*t.^2)

This is the code I have now and I'm having trouble getting the x and y equations to work.

Please help. Thanks in advance.

Best Answer

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')

Related Solutions

MATLAB: I need to plot the amplitude of the signals

Try not using so many elements - too many to display.

Try this:

clc;
close all;
clear;
workspace;
format long g;
format compact;
fontSize = 15;
%variables
Am=5; %message signal amplitude

Ac=10; %message signal amplitude
t= linspace(0, 0.04, 1500); %period
Fm=50; %message frequency
Fc=1000; %carrier frequency
%output graph preparation
m=Am*cos(2*pi*Fm*t); % Signal equation
c=Ac*cos(2*pi*Fc*t); % Carrier equation
%plot m(t) and its amplitude
subplot(2,3,1);
plot(t,m);
xlabel('time', 'FontSize', fontSize);
ylabel('m(t)', 'FontSize', fontSize);
title('Signal Equation', 'FontSize', fontSize);
% Put x axis in the right place.



ax = gca
ax.XAxisLocation = 'origin'
subplot(2,3,2);
plot(t,abs(m));
xlabel('time', 'FontSize', fontSize);
ylabel('m(t)', 'FontSize', fontSize);
title('Signal Amplitude', 'FontSize', fontSize);
%plot c(t) and its amplitude
subplot(2,3,3);
plot(t,c);
xlabel('time', 'FontSize', fontSize);
ylabel('c(t)', 'FontSize', fontSize);
title('Carrier Equation', 'FontSize', fontSize);
% Put x axis in the right place.
ax = gca
ax.XAxisLocation = 'origin'
subplot(2,3,4);
plot(t,abs(c));
xlabel('time', 'FontSize', fontSize);
ylabel('c(t)', 'FontSize', fontSize);
title('Carrier Amplitude', 'FontSize', fontSize);
% Put x axis in the right place.
ax = gca
ax.XAxisLocation = 'origin'
%Sketch the magnitude of the multiplication of m(t) with c(t).
y=m.*c;
subplot(2,3,5);
plot(t,y);
xlabel('time', 'FontSize', fontSize);
ylabel('m(t) .* c(t)', 'FontSize', fontSize);
title('Multiplication of m(t) with c(t)', 'FontSize', fontSize);
% Put x axis in the right place.
ax = gca
ax.XAxisLocation = 'origin'
subplot(2,3,6);
plot(t,abs(y));
xlabel('time', 'FontSize', fontSize);
ylabel('y(t)', 'FontSize', fontSize);
title('Amplitude of the multiplication', '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: Plot range -pi to pi

Try this:

% 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 long g;
format compact;
fontSize = 20;
theta = linspace(-pi, pi, 1000);
period = 3*pi/4;  % Whatever you want.
sint = sin(2 * pi * theta / period);
plot(theta, sint, 'b-', 'LineWidth', 2);
hold on;
cosinet = cos(2 * pi * theta / period);
plot(theta, cosinet, 'r-', 'LineWidth', 2);
tant = tan(2 * pi * theta / period);
plot(theta, tant, '-', 'Color', [0, 0.5, 0], 'LineWidth', 2);
grid on;
xlabel('Theta [in radians]', 'FontSize', fontSize);
ylabel('Amplitude (signal value)', 'FontSize', fontSize);
title('Trig functions versus Theta', 'FontSize', fontSize);
legend('Sine', 'Cosine', 'Tangent');
% The tangent spikes are so big that we can't see the sin and cosine.
% Let's limit the y range to +/- 4;
ylim([-4, 4]);
% 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')

Best Answer

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MATLAB: I need to plot the amplitude of the signals

MATLAB: Plot range -pi to pi

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