$\"\"$

\

The expression is $\"\"$ .

\

Consider $\"\"$ then $\"\"$ .

\

The expression can be written as $\"\"$ :

\

$\"\"$

\

Here $\"\"$ and $\"\"$ .

\

Pythagoras rule : $\"\"$ .

\

$\"\"$

\

$\"\"$

\

$\"\"$ .

\

Therefore $\"\"$ .

\

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

\

$\"\"$

\

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