How can i make this loop start at theta= zero and evaluate the same equations for values increasing by two (e.i at 0,2,4,6 etc.)

n=(360/Dth)+1

Trial>> for I=1:2:n R=12

w=(2*pi/5) Md=50 Theta=0 Thetarads= theta*pi/180

Id=(.5*Md*R^2)

Mp=75

Mb=30

alpha=0 u=.8 L=6*R theta=0 Dth=2 thetarads=theta*pi/180 rx=(R)*cos(theta)-L*cos(180)-L ry=(R*sin(theta))-(L*sin(180))-(R*sin(theta)) vx=(-R)*(w)*sin(theta) vy=(R)*(w)*cos(theta) alpha=0 ax=(-R)*alpha*sin(theta)-(R*(w^2)*cos(theta)) ay=(R)*alpha*cos(theta)-(R*w^2*sin(theta)) theta=theta+Dth end

[Chad Greene]

What equations do you need to evaluate for each I? It's generally good to do as little as possible inside a loop. For example, you can evaluate Mp=75 just once before the loop rather than computing it every time.

A small note: It's much easier to read and run your code if you can format it using the {}Code button when posting a question.

[Emily Gobreski]

I am trying to evaluate ax,ay,rx,ry,and ax,ay. They all have theta values. I am trying to get the theta values to run from 0 to 360, testing values every 2 degrees. Thank you for the advice. i am new to this. I really appreciate your time.

Answer 1

[Chad Greene]

Here's how you'd get ax and ay. First we define an array of values theta which go from 0 to 360 in steps of 2. Then we say for each value of theta, compute a corresponding value of ax and ay. I'm using k as a counter which goes through each index in theta.

R = 12; 
w = 2*pi/5; 
alpha = 0; 
theta = 0:2:360; 

for k = 1:length(theta) 
   ax(k)=(-R)*alpha*sind(theta(k))-(R*(w^2)*cosd(theta(k))) ;
   ay(k)=(R)*alpha*cosd(theta(k))-(R*w^2*sind(theta(k))) ;
end

[Chad Greene]

Here are the plotted results of ax and ay:

plot(ax,ay) 
axis equal

[Emily Gobreski]

You are wonderful, thank you so much! i really appreciate it.