How can I fix this program. I've never used MatLab, but I need to be able to input theta and get a y and x value for it.

function [X, Y] = mathModelOfCamAndFollower(theta)

%Initialize the design parameters
theta0 =0;
theta1 = 120;
theta2 = 120.1;
theta3 = 240;
theta4 = 360;
fd = 2; % difference between maximum follower displacement and minimum cam radius

%Convert degree to radian
theta0 =theta0*pi/180;
theta1 =theta1*pi/180;
theta2 =theta2*pi/180;
theta3 =theta3*pi/180;
theta4 =theta4*pi/180;

%Initialize the parameters for the displacement diagram
D = 12;
d1 = D*(theta1 - theta0)/(theta4-theta0);
d2 = D*(theta2 - theta1)/(theta4-theta0);
d3 = D*(theta3 - theta2)/(theta4-theta0);
d4 = D*(theta4 - theta3)/(theta4-theta0);

phi1 = atan(fd/d1);
phi2 = atan(fd/d3);

if theta <theta1
    %formula during rise
    X = d1*(theta1-theta)/(theta1 -theta0);
    Y = tan(phi1)*X;
else % Executes only when theta is not less than theta1
    if theta <theta2
        %formula during dwell
        X = d1+d2*(theta-theta1)/(theta2-theta1);
        Y = fd;
    else 
        if theta <theta3
            %formula during fall
            X = d1+d2+d3*(theta-theta2)/(theta3-theta2);
            Y = tan(phi2)*(1-X);
        else 
            if theta <theta4
                %formula during dwell2
                X = d1+d2+d3+d4*(theta-theta3)/(theta4-theta3);
                Y = 0;
            end
        end
    end 
end

Answer 1

[Geoff Hayes]

Don - what is wrong with the code that it needs to be fixed? The theta input is a positive angle in radians. To get the x and y output, just call the function as

 theta = 5*pi/180;  % convert theta from degrees to radians
 [x,y] = mathModelOfCamAndFollower(theta);

Answer 2

[Image Analyst]

I didn't study or run the code but I do see you assigning x and y in there, like you asked for. What's wrong? Do you know that there are "d" versions of the trig functions where you can pass in degrees instead of radians, like atan2d() instead of atan2()?