graph (some basic)

I wanna know if we wish to plot graph and its based on some equations result, of for example Temperature vs time.. and the values I wish to have on X as (t:dt:tend) and this values are inputs..to draw graph for y axis as calculated value of Temperature..

I am trying this way

x = [t : dt: tend];
y = Tn;
figure
plot(x, y, 'r')  

But I am not getting the result; because I learned that y got to be the function of x, but I dont know what to use as if u use f(x) its not accepting here, so what else I can do

[Geoff Hayes]

Nishaben - what is Tn? Is that a function or a variable?

[Walter Roberson]

Probably

x = t : dt: tend;
y = Tn(x);
figure
plot(x, y, 'r')  

[Nishaben Desai]

Geoff,

Tn is the Temperature, and it is variable, but I know it still isnt right one here is how it looks like, the entire codes look like this

prompt = 'What is the value of Area, A? ';
A = input(prompt)
prompt = 'What is the value of Heat Transfer Coefficient, h? ';
h = input(prompt)
prompt = 'What is the value of Temperature of System, Ts? ';
Ts = input(prompt)
prompt = 'What is the value of Temperature of Surroundings, Tf? ';
Tf = input(prompt)
prompt = 'What is the value of mass, m? ';
m = input(prompt)
prompt = 'What is the value of Heat Capacity, c? ';
c = input(prompt)
prompt = 'What is the value of time interval, dt? ';
dt = input(prompt)
prompt = 'What is the value of time at the end, tend? ';
tend = input(prompt)
 t = 0;
 q2 = 150;
while t<tend
q1 = - A*h*(Ts - Tf)
Q = (q1+q2)*dt
Tn = (Q/(m*c)) + Ts 
Ts = Tn;
t = t+dt;
end 

I can also have option to plot graph of time t vs temperature Tn, where they can take direct value from the loop.; but it still doesnt seem working

[Nishaben Desai]

Dear Walter, I would try what options you sent. My only problem happening is,, graph isnt showing any movement. its blank

Answer 1

[Walter Roberson]

prompt = 'What is the value of Area, A? ';
A = input(prompt)
prompt = 'What is the value of Heat Transfer Coefficient, h? ';
h = input(prompt)
prompt = 'What is the value of Temperature of System, Ts? ';
Ts = input(prompt)
prompt = 'What is the value of Temperature of Surroundings, Tf? ';
Tf = input(prompt)
prompt = 'What is the value of mass, m? ';
m = input(prompt)
prompt = 'What is the value of Heat Capacity, c? ';
c = input(prompt)
prompt = 'What is the value of time interval, dt? ';
dt = input(prompt)
prompt = 'What is the value of time at the end, tend? ';
tend = input(prompt)
 q2 = 150;
 
 tvals = 0 : dt : tend;
 num_t = length(tvals);
 Tn = zeros(1, num_t);
 for tidx = 1 : num_t
     t = tvals(tidx);
     q1 = - A*h*(Ts - Tf);
     Q = (q1+q2)*dt;
     Ts = (Q/(m*c)) + Ts;
     Tn(tidx) = Ts;
 end
 plot(tvals, Tn);

[Nishaben Desai]

Let me try and get back to you.. thanks you so so much.. indeed

[Nishaben Desai]

yap. It looks awesome, I learned this now, of how to plot graph like this.

Tons and tons and tons of thanks for saving so much of my time. I been struggling and trying since last week.

Nisha