$\"\"$

(a)

The expression is $\"\"$ .

Use the properties of inverse trigonometric function: $\"\"$

$\"\"$

The exact value of expression $\"\"$

$\"\"$

(b)

The expression is $\"\"$ .

Use the properties of inverse trigonometric function: $\"\"$ .

$\"\"$ .

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

$\"\"$

(a)

The exact value of the expression $\"\"$ is 10.

(b)

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