(Solved):
Let \( \alpha \) and \( \beta \) be first quadrant angles with \( \cos (\alpha)=\frac{\sqrt{3}}{2} ...
Let \( \alpha \) and \( \beta \) be first quadrant angles with \( \cos (\alpha)=\frac{\sqrt{3}}{2} \) and \( \sin (\beta)=\frac{\sqrt{3}}{4} \). Find \( \cos (\alpha+\beta) \)