Signal is periodic or not

[Parth86]

Hello
I understand that signal is periodic if it repeat after fixed time
Look at example

I know the signal is periodic because it repeat after 2pi period. 2pi,4pi,6pi.....20pi
How to find out that signal is periodic or not?

 

[crutschow]

It's periodic if it continues foreever with the same pattern.

 

[Parth86]

It's periodic if it continues foreever with the same pattern.

Yes I agree but how to find out using example. So I tried with example. I know the condition for periodic signal but I really don't understand the logic behind condition