$\"\"$

\

The expression is $\"\"$ .

\

Rewrite the expression $\"\"$ .

\

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

\

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

\

$\"\"$

\

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

\

Pythagoras rule : $\"\"$ .

\

$\"\"$

\

$\"\"$

\

$\"\"$ .

\

Therefore $\"\"$ .

\

Hence $\"\"$ .

\

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

\

$\"\"$

\

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