signals and systems

Joined Aug 10, 2008
1
Huy guys....have the following questions from signals and systems....

Determine whether the following signals is periodic...If it is periodic determine its fundamental period....

a) 2cos(9t+pi/6)
b) x(t) = sin^2(t-pi/6)
c)x[n] = cos((pi*n^2)/8)
d)x[n] = 5sin((3pi/8)*n) + 3cos((pi/6)*n)

I have attached the file with the questions.....

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roddefig

Joined Apr 29, 2008
149
See [post]78406[/post].

silvrstring

Joined Mar 27, 2008
159
That's nice. Where's your work?

roddefig

Joined Apr 29, 2008
149
That's nice. Where's your work?
What do you mean?

Edit: Ack, sorry, I thought silvrstring was the OP. Disregard my question.

Last edited:

blazedaces

Joined Jul 24, 2008
130
Huy guys....have the following questions from signals and systems....

Determine whether the following signals is periodic...If it is periodic determine its fundamental period....

a) 2cos(9t+pi/6)
b) x(t) = sin^2(t-pi/6)
c)x[n] = cos((pi*n^2)/8)
d)x[n] = 5sin((3pi/8)*n) + 3cos((pi/6)*n)

I have attached the file with the questions.....
roddefig gave you your answer. We're not here to do your homework for you.

But just to add a comment, it might help for part d to know that the sum of two periodic signals is periodic if the ratio of their individual fundamental frequencies is a rational number.

Think about the concept. Periodic. Plot each of those out using matlab or a calculator and look at the signals. Periodic means it repeats. Now think about that and think about the info roddefig gave you. You can easily connect the dots.

Good luck,
-blazed