Plotting a time series e^(-at) cos⁡((bt) u_s (t)) for two cases, first for a=3 and b=50, then for a=-3 and b=50.

I have been trying to plot the time series (e^(-at)*cos(bt)*u_s(t))) for two cases, first for a=3 and b=50, then for a=-3 and b=50 . Plot both cases on the same plot. Let the vertical axis span from -6 to 6 and the horizontal axis from 0 to 1 seconds.

Please help me rewrite this code:

a1=3; 
b1=50; 
a2 = -3;
b2= 50; 
f1 = exp^(-a1*t)*cos(b1*t)*u(t); 
f2 = exp^(-a2*t)*cos(b2*t)*u(t); 
ts1 = timeseries (f1,0:1); 
ts2 = timeseries(f2,0:1);
ts1.Name = 'time series';
ylim(-6:6); 
plot(ts1); 
hold on
plot(ts2); 

[Torsten]

What is u(t) ?

[Dyuman Joshi]

An error occurs in this line -

ylim(-6:6); 

This is not how ylim works.

From the documentation - "Specify limits as a two-element vector of the form [ymin ymax], where ymax is greater than ymin."

And you don't need to define the variables as timeseries object. Plot directly, as has been show below.

You can also use fplot

Answer 1

[KSSV]

clc; clear ;
a1=3; 
b1=50; 
a2 = -3;
b2= 50; 

t = linspace(0,1) ; 

f1 = exp(-a1*t).*cos(b1*t) ; 
f2 = exp(-a2*t).*cos(b2*t); 

plot(t,f1,'r'); 
hold on
plot(t,f2,'b');
ylim([-6 6])
legend('f1','f2')