Why can't I get exact cosine waveform?

I write following in my MATLAB to generate cosine plot. Why the peak of this wave is like triangular shape? is it a problem with plot() command?

>> t = 0:1*10^-3:40*10^-3; >> v = 120*1.41*cos(120*pi*t); >> i = (5*1.41/6)*cos(120*pi*t); >> p = v.*i; >> plot(t,p);

Answer 1

[Star Strider]

Your t vector only produces 41 points to evaluate. Change it to:

t = linspace(0,40E-3,250);

to create a vector over the same interval with 250 points. That should smooth it.

[Aalok Bhatt]

That indeed work. Thank you for this wonderful answer..:).

[Star Strider]

My pleasure!