$\"\"$ is an odd function.

From the definition of odd function: $\"\"$ .

If $\"\"$ is an odd function, then prove $\"\"$ .

If $\"\"$ is an even function, then prove $\"\"$ .

The equality is $\"\"$ .

Substitute $\"\"$ in $\"\"$ .

$\"\"$

Apply the transitive property: $\"\"$ then $\"\"$ .

$\"\"$

Therefore, $\"\"$ is an even function.

$\"\"$ is an even function.