Hi, my question is whether the sum and multiplication of two periodic functions (with a common period) are periodic.
Our functions are R[itex]\rightarrow[/itex]R.
The Attempt at a Solution
f(x)=f(x+T) g(x)=g(x+T) T is the period.
Hence, h(x) is also periodic.
What I did is similar for multiplication. Is there any flaw in this? I searched a bit and found out this may not hold every time, but I guess that was about Fourier series, which I have no idea about.
Thanks for any hint :)