Is this function periodic:
x(t) = 2 cos(10πt − π/5) cos(πt + 2π/5)
I don't want an actual answer (honor code hassles), I just want to know if my thinking is correct. Since I cannot combine these two cosines together (they have different frequencies and offsets), they won't line up i a repeating periodic manner. Any tips/correction to my approach?

Question

Is this function periodic:
x(t) = 2 cos(10πt − π/5) cos(πt + 2π/5)
I don't want an actual answer (honor code hassles), I just want to know if my thinking is correct. Since I cannot combine these two cosines together (they have different frequencies and offsets), they won't line up i a repeating periodic manner. Any tips/correction to my approach?

loser66 · Answer

I don't know how to explain, but the graph shows it is periodic.

loser66 · Answer

https://www.desmos.com/calculator/vlafwdvfsz

anonymous · Answer

Thanks. I will ask my TA about the mathy part.

loser66 · Answer

You have TA? that is you are in higher level of math, right?

anonymous · Answer

I am in college. This is a review question for a signals class.

loser66 · Answer

engineer?

loser66 · Answer

if it is so, then @dan815  is a perfect guy for this. I am a math student. :)