The <em>trigonometric</em> expression is equivalent to the <em>trigonometric</em> expression.
<h3>How to prove a trigonometric equivalence</h3>
In this problem we must prove that <em>one</em> side of the equality is equal to the expression of the <em>other</em> side, requiring the use of <em>algebraic</em> and <em>trigonometric</em> properties. Now we proceed to present the corresponding procedure:
The <em>trigonometric</em> expression is equivalent to the <em>trigonometric</em> expression.