$\"\"$

The trigonometric expression is $\"\"$ .

Let $\"\"$ , then $\"\"$ .

Draw a right triangle with an acute angle $\"\"$ .

Label the sides such that $\"\"$ .

Then use the Pythagorean theorem to express the length of the third side.

$\"\"$

From the diagarm :

$\"\"$ .

Apply tangent sum identity : $\"\"$ .

$\"\"$

Substitute the values $\"\"$ and $\"\"$ .

$\"\"$

Therefore, $\"\"$ .

$\"\"$

$\"\"$ .