Plotting the Orbit of planets with MATLAB

[cannibal]

Homework Statement

Hi everyone, i was presented with this problem in my Computer Programming for Engineers Class.

The orbit of the planets around the sun can approximately be
modeled by the polar equation:

[URL]http://www.prml.org/images/71715equation.PNG[/URL]The values of the constants P and e for four planets are given
below. Plot the orbits of the four planets in one figure (use the hold
on command).

Planet----|----P (x^10^6 m)----|e------------Planet----|----P(x^10^6 m)----|e
Mercury-------269.2-------------0.206---------Earth---------8964-------------0.0167
Venus---------15913-------------0.00677-------Mars---------2421-------------0.0934

Homework Equations

[URL]http://www.prml.org/images/71715equation.PNG[/URL]

The Attempt at a Solution

Can anyone approach me to how i can begin this problem ? i have no idea of even how to begin it

 

[LeBrad]

Just evaluate the expressions for a range of theta for each value of P and e.

polar(theta,R) makes polar plots in Matlab.

Have you ever used Matlab before?

 

[cannibal]

Just evaluate the expressions for a range of theta for each value of P and e.

polar(theta,R) makes polar plots in Matlab.

Have you ever used Matlab before?

Well i have used it but, i was not introduced to plotting

 

[cannibal]

Code:
t=0:pi/40:2*pi;
P=200;
e=0.2;
R=e*P./(1-e*cos(t));
polar(t,R);
--------------------
Maxim Vedenev, Matlab freelancer, vedenev@ngs.ru
http://simulations.narod.ru/matlab/

Thank you very much vedenev that worked :D and thanks to LeBrad too. When i finish the exercise I will post it here.

 

[cannibal]

Okay :D i just finished i came up with this script, any suggestions ?, once again thanks to vedenew and LeBrad.

Problems:

1. Single planets orbits are plotting without Title.
2. I would like the "All planets" plot to be in a Polar Paper
3. Anyway i can make the orbits move ? i mean like do a circular motion ?


Thanks

%Global Variables Begin
op=0; clc
z=0:pi/40:2*pi;
%Global Variables Ends

%User Menu Begins
while op~=6 
disp ('Planet Orbit Plotter')
disp('1)Mercury')
disp('2)Venus')
disp('3)Earth')
disp('4)Mars')
disp('5)All')
disp('6)Exit')
op = input ('Please choose an option: ');
%User Menu Ends

switch op
    case 1 %Mercury's Orbit
        
        TITLE('Mercury''s Orbit')
        P=269.2;
        e=.206;
        R=(e*P)./(1-e*cos(z));
        polar(z,R,'m . -');
        pause
        
    case 2 %Venus Orbit
        
        TITLE('Venus Orbit')
        hold on
        P=15913;
        e=.00677;
        R=(e*P)./(1-e*cos(z));
        polar(z,R,'c . -');
        pause
        
    case 3 %Earth's Orbit
        
        TITLE('Earth''s Orbit')
        hold
        P=8964;
        e=.0167;
        R=(e*P)./(1-e*cos(z));
        polar(z,R,'b . -');
        pause
        
    case 4 %Mars Orbit
        
        title ('Mars Orbit')
        hold on
        P=2421;
        e=.0934;
        R=(e*P)./(1-e*cos(z));
        polar(z,R,'R . -');
        pause
        
    case 5 % All four orbits
        
        TITLE('Mercury, Venus, Earth and Mars Orbits')
        
        hold all
        %Mercury Orbit
        P=269.2;
        e=.206;
        R=(e*P)./(1-e*cos(z));
        polar(z,R,'m . -'); grid on
        
        %Venus Orbit
        P=15913;
        e=.00677;
        R=(e*P)./(1-e*cos(z));
        polar(z,R,'c . -'); grid on
        
        %Earth's Orbit
        P=8964;
        e=.0167;
        R=(e*P)./(1-e*cos(z));
        polar(z,R,'b . -'); grid on
        
        %Mars Orbit
        P=2421;
        e=.0934;
        R=(e*P)./(1-e*cos(z));
        polar(z,R,'R . -'); grid on
        
        legend('First','Second','Third','Fourth');
        legend('Mercury','Venus','Earth','Mars','Location','EastOutside')
        
    otherwise
        break
end
clc
end