Plotting exponential periodic function

Hi There!

I'd like to plot the following function with matlab as a theta function

but the graphs looks completely wrong.

What should I do?

Answer 1

[Catalytic]

What should you do? You should correct whatever mistake it is you made.

[Nico Pisani]

There are no code mistakes. Simply the graph is not the one I expect...

Here is what I typed in:

x = linspace(0,2*pi,100);

y = ((1-exp(-1.9./cos(x)))./(1-exp(-1.9))).*cos(x);

plot(x,y)

I