Understanding Power Signals and Non-Periodic Functions

[Angello90]

x(t) = t, $$0 \leq t \leq 1$$;
x(t) = 2-t, $$1 \leq t \leq 2$$;
x(t) = 0 ,otherwise.

I want to draw this signal, and I have something similar to this

Is that correct? Also this is not periodic right? I just want to be sure 100%

Thanks!

 

[berkeman]

x(t) = t, $$0 \leq t \leq 1$$;
x(t) = 2-t, $$1 \leq t \leq 2$$;
x(t) = 0 ,otherwise.

I want to draw this signal, and I have something similar to this

Is that correct? Also this is not periodic right? I just want to be sure 100%

Thanks!

Looks good to me.

 

[Angello90]

Ok thanks a lot;)

Also if:
$$x[n] = Cos(\pi n), n\geq 0$$
$$x[n] = 0, otherwise$$,

Than graph will be periodic from $$0 \rightarrow \infty$$, but from $$- \infty \rightarrow \infty$$ it is not periodic right? So overall is it periodic or not? My books says that it is periodic.

 

[berkeman]

Ok thanks a lot;)

Also if:
$$x[n] = Cos(\pi n), n\geq 0$$
$$x[n] = 0, otherwise$$,

Than graph will be periodic from $$0 \rightarrow \infty$$, but from $$- \infty \rightarrow \infty$$ it is not periodic right? So overall is it periodic or not? My books says that it is periodic.

What is your book's definition of a periodic function? Usually it has to hold for all x, not just a range:

http://en.wikipedia.org/wiki/Periodic_function

.

 

[Angello90]

Sorry I shouldn't write that it says it's periodic. It says that it is power signal, but power signal is periodic hence my statement.

So the function x[n] is not periodic?