$\"\"$

The expression is $\"\"$ .

Let $\"\"$ .

Take the angle $\"\"$ in the interval $\"\"$ .

$\"\"$

Definition of $\"\"$ .

$\"\"$ .

\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \

$\"\"$	$\"\"$	$\"\"$	$\"\"$	$\"\"$	$\"\"$	$\"\"$	$\"\"$	$\"\"$	$\"\"$
$\"\"$	$\"\"$	$\"minus$	$\"minus$	$\"minus$	$\"\"$	$\"1$	$\"\"$	$\"\"$	$\"\"$

Observe the table, $\"\"$ possible if $\"\"$ .

Thus, the value of $\"\"$ is $\"\"$ .

$\"\"$

The value of $\"\"$ is $\"\"$ .