There are multiple issues here, and it will be up to you to decide how to address them.
This is what I can provide:
You do not specify an x-coordinate for your plot command. That can be done, however, Matlab will use the index of the vector for the x-axis. Example: if you have
y = 1:2:6; plot(y); hold on; y = 1:1:6; plot(y);
you'll see the difference.
How does this apply to your case? You specify a vector of higher resolution (t_i
, compared tot
), but in your plot command you do not provide this new vector for the x-coordinate.Your definition of
c_t
provides very very small values (on the order of10^-77
). And from t > 60, your output is indifferent from 0.
How does that effect your interpolation?
You specify that for the interval[0 60]
you want step-sizes of 15 - that does not give you a lot of resolution:You might want to change to something like:
t_i =[0:0.5:60,90:30:120,180:60:240,440:200:2240];
Which will give you this plot:
In either case, I do not understand why you chose a data range above 60 (all the way until 3000) for the data you are trying to plot. This explains why you do not see anything with your axis limits
axis([0 3000 -2000 80000]);
that by far exceed the range of y-values and obscures the non-zero data entries for small x.