1. Let's clarify the context of step 5 where $\alpha$ is divided by 2. 2. Often in trigonometry or geometry problems, dividing an angle $\alpha$ by 2 is related to using half-angle formulas or finding the measure of an angle bisector. 3. For example, in the half-angle formula for sine: $$\sin\left(\frac{\alpha}{2}\right) = \pm \sqrt{\frac{1 - \cos\alpha}{2}}$$ the angle is halved to simplify expressions or solve for unknowns. 4. Dividing $\alpha$ by 2 can also be necessary when the problem involves bisecting an angle, meaning splitting it into two equal parts. 5. Without the exact problem statement, the general reason for dividing $\alpha$ by 2 is to apply half-angle identities or to work with angle bisectors, which are common techniques in trigonometry and geometry. 6. If you provide the full problem or step 5 details, I can give a more precise explanation.