$\"\"$

The function is $\"\"$ .

Suppose that there exists a number $\"\"$ , $\"\"$ , for which $\"\"$ for all $\"\"$ .

Then, if $\"\"$ , then $\"\"$ , so $\"\"$ .

if $\"\"$ , then $\"\"$ , but $\"\"$ .

$\"\"$ .

This is impossible.

Thus, the smallest positive number $\"\"$ for which $\"\"$ for all $\"\"$ is $\"\"$ .

Therefore, the period of $\"\"$ is $\"\"$ .

$\"\"$

The period of $\"\"$ is $\"\"$ .