How to incorporate positive and negative theta while plotting graph for Range vs theta in projectile motion

I am trying to write a code to plot a graph for Range vs theta for projectile motion and using it in LABVIEW. I don't know how to incorporate θ as positive and negative when above and below the horizontal. Below is the code I have written for LABVIEW's MATLAB script

v

g = 9.8

H

V = v.*v

G = 2.*g

theta = linspace(0,90,91)
a = 2.*theta
b = sin(a)
c = b.*b
d = V/G
e = 8.*g.*H /V

A = sqrt((sin(a)).^2+e.*(cos(theta)).^2)

R = d.*[a+A]

Answer 1

[Image Analyst]

linspace can take negative values, you know.

http://www.mathworks.com/matlabcentral/answers/13205#answer_18099

My projectile demo is attached.

[Peter Walt]

Thank you very much for your reply. I am struggling to write a code for the following problem.

I have to write a code for plot range vs theta. I have to plot this for angle 0 to 90 with spacing 1(0,1,2,3,...90) I tried but getting a straight line. Can you please help me.

[Image Analyst]

Try this:

v = 10;
g = 9.8;
H = 7;

theta = linspace(0,90,91)
term1 = v^2/(2*g);
term2 = sind(2 * theta);
term3 = term2 .^ 2;
term4 = (8*g*H/v^2) * cosd(theta) .^ 2;
R = term1 * (term2 + sqrt(term3 + term4))

plot(theta, R, 'b*-', 'LineWidth', 2);
grid on;
title('R versus Theta', 'FontSize', 20);
xlabel('Theta in degrees', 'FontSize', 20);
ylabel('R', 'FontSize', 20);

%------------------------------------------------------------------------------
% Set up figure properties:
% Enlarge figure to full screen.
set(gcf, 'Units', 'Normalized', 'OuterPosition', [0, 0.04, 1, 0.96]);
% 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')

[Peter Walt]

Thank you very much. I really appreciate your help. What does 'b*-' means?

[Peter Walt]

I understand a bit that your are multiplying with '-' sign but I did not understand what is 'b'. Sorry, I am new to MATLAB. Thanks

[Steven Lord]

No, in that context 'b*-' is a line specification. Specifically it tells plot to plot a blue (b) solid line (-) with asterisks (*) as markers.

[Peter Walt]

thank you very much for your effort in answering it. Got the correct one.