How to plot c(t) vs t

How to plot c(t) vs t with these parameters for various values of v

c(t)=c0-c03*k*(1/cmin-1/cmax)*v*u(t)

where,

u(t)=1,  t≥0
         0, t<0
Cmin=10e-9
Cmax=10e-6
C0=100e-9
K=10e6

Thanks in advance

Answer 1

[Yu Jiang]

I would first define a function as follows:

function y = Cfun(t, v)
   u = double(t>=0);
   Cmin = 10e-9;
   Cmax = 10e-6;
   C0 = 100e-9;
   K = 10e6;
   C03 = C0;  % I don't know what C03 is, so I set it the same as C0.
   y = C0-C03*K*(1/Cmin-1/Cmax)*v*u;
end

Then, create a different MATLAB file with the following code

t = linspace(-10,10,100);
y = [];
for v = [1,5,-1,-5]
 y = [y; Cfun(t,v)];
end
plot(t,y(1,:),t,y(2,:),t,y(3,:),t,y(4,:))
legend('v=1', 'v=5', 'v=-1', 'v=-5')

Then, you should be able to see the figure as expected.

-Yu

[Yu Jiang]

Did you save the function as a separate MATLAB file with the filename "Cfun.m"?

[vetri veeran]

Finally i got the answer. Thank you. But I need to change the function used in u as step function. can u tell me how it can be achieved.For v, I need to pass different values like v=1,5,-1,-5 and I have to plot all the values of c(t) using different values of v in the same plot. Thanks in advance.

[Yu Jiang]

Sure.

To change u as a step function, you can simply try

u = double(t>=0);

To plot the data with different v, you can use a for loop. I have revised my original answer and you can directly use the code there.

[vetri veeran]

function y = Cfun(t, v) u = double(t>=0); Cmin = 10e-9; Cmax = 10e-6; C0 = 100e-9; K = 10e6; C03 = C0; % I don't know what C03 is, so I set it the same as C0. y = C0-C03*K*(1/Cmin-1/Cmax)*v*u; end And I typed following given below code in the command window. t = linspace(-10,10,100); y = []; for v = [1,5,-1,-5] y = [y; Cfun(t,v)]; end plot(t,y(1,:),t,y(2,:),t,y(3,:),t,y(4,:)) legend('v=1', 'v=5', 'v=-1', 'v=-5')

Where i am getting an error as Undefined function 'Cfun' for input arguments of type 'double'. I am unable to find the error.can you help me in this regard.

[Yu Jiang]

Did you put them into to different MATLAB files and execute the script file? It seems to me that you are executing the function file.