If a function is periodic with a period of \(4\), what is \(f(x + 4)\)?

For a function that is periodic with a period of (4), it means that the function repeats its values every (4) units along the (x)-axis. Therefore, for any value of (x), the output of the function at (x) is the same as the output at (x + 4). This relationship can be expressed mathematically as:

[ f(x + 4) = f(x) ]

This demonstrates that the value of the function at (x + 4) is equivalent to the value at (x), reinforcing the definition of periodicity. Consequently, when asked what (f(x + 4)) is, the correct answer is indeed (f(x)).