# Periodic signal

• Jul 23rd 2011, 02:31 AM
anderson
Periodic signal
Hi everyone

Determine if each of the following CT signals is periodic. If periodic find it period.
a) x(t)=2sin(10$\displaystyle \pi$t-30degrees)
b) x(t) = 2 cos ($\displaystyle \sqrt$2$\displaystyle \pi$t)
c)x(t) = 2 sin ($\displaystyle \sqrt$$\displaystyle \pit) d) x(t) = 2 cos (t+ 60degrees) • Jul 23rd 2011, 02:57 AM mr fantastic Re: Periodic signal Quote: Originally Posted by anderson Hi everyone I really dont know how to start this questions, please help me. Thank you in advance for all your help & support. Determine if each of the following CT signals is periodic. If periodic find it period. a) x(t)=2sin(10\displaystyle \pit-30degrees) b) x(t) = 2 cos (\displaystyle \sqrt2\displaystyle \pit) c)x(t) = 2 sin (\displaystyle \sqrt$$\displaystyle \pi$t)
d) x(t) = 2 cos (t+ 60degrees)

You're meant to know that the sine and cosine functions are periodic. What knowledge do you have those functions and where are you stuck in applying that knowledge to your current questions?
• Jul 23rd 2011, 02:59 AM
anderson
Re: Periodic signal
Thank you for your response. Need an example so that I can understand the question. Appreciate if anyone can help to solve.
• Jul 23rd 2011, 03:06 AM
mr fantastic
Re: Periodic signal
Quote:

Originally Posted by anderson
Thank you for your response. Need an example so that I can understand the question. Appreciate if anyone can help to solve.

You're meant to know that the sine and cosine functions are periodic. What knowledge do you have those functions and where are you stuck in applying that knowledge to your current questions?
• Jul 23rd 2011, 03:08 AM
anderson
Re: Periodic signal
Sine and cosine are periodic, i think that is what you are saying. How do i find the period if it is periodic.
• Jul 23rd 2011, 03:10 AM
mr fantastic
Re: Periodic signal
Quote:

Originally Posted by anderson
Sine and cosine are periodic, i think that is what you are saying. How do i find the period if it is periodic.

Look, this is the third time I've had to ask: What have you learned about sine and cosine functions?
• Jul 23rd 2011, 03:15 AM
anderson
Re: Periodic signal
Nothing, that is why I am asking for help. If someone can do the first question, then I can use it as an example. Hope this answers your question.
• Jul 23rd 2011, 03:21 AM
mr fantastic
Re: Periodic signal
Quote:

Originally Posted by anderson
Nothing, that is why I am asking for help. If someone can do the first question, then I can use it as an example. Hope this answers your question.

I find that hard to believe. I'm mighty surprised that a subject that would set questions like these does not require knowledge of trigonometric functions as a pre-requisite for enrolment.

If true, I suggest that you review some websites found by Google: Google

Getting a hold of a textbook that covers basic trigonometric functions would also be prudent.

Do you know the difference between degrees and radians? If not, I suggest you review that material as well.
• Jul 23rd 2011, 03:22 AM
anderson
Re: Periodic signal
Thanks but no thanks.If you can't help, please dont reply. Thank you & regards.
• Jul 23rd 2011, 03:36 AM
mr fantastic
Re: Periodic signal
Quote:

Originally Posted by anderson
Thanks but no thanks.If you can't help, please dont reply. Thank you & regards.