<p>Prove the following identities.</p>
<ol class="i-list"><li data-list-item-id="item-i"><div class="list-item-paragraph">\(\frac{1 - \tan^2 \frac{A}{2}}{1 + \tan^2 \frac{A}{2}} = \cos A\)</div></li><li data-list-item-id="item-ii"><div class="list-item-paragraph">\(\left( \sin \frac{A}{2} + \cos \frac{A}{2} \right)^2 = 1 + \sin A\)</div></li></ol>

\[\frac{1 - \tan^2 \frac{A}{2}}{1 + \tan^2 \frac{A}{2}} = \cos A\]

\(\frac{1 - \tan^2 \frac{A}{2}}{1 + \tan^2 \frac{A}{2}} = \cos A\)

\[\left( \sin \frac{A}{2} + \cos \frac{A}{2} \right)^2 = 1 + \sin A\]

\(\left( \sin \frac{A}{2} + \cos \frac{A}{2} \right)^2 = 1 + \sin A\)

Trigonometry - Compound and Double-Angle Identities

Trigonometry - Compound and Double-Angle Identities

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