Chapter 5 - Section 5.2 - Sum and Difference Formulas - 5.2 Problem Set - Page 288: 9

$\sin15^{\circ} =(\frac{\sqrt 6 - \sqrt 2}{4})$

$\sin15^{\circ}$ = $sin(A−B)=sin(A)cos(B)−cos(A)sin(B)$ $sin(60−45)=sin(60)cos(45)−cos(60)sin(45)$ $\sin15^{\circ} =(\frac{\sqrt 3}{2})(\frac{\sqrt 2}{2})-(\frac{1}{2})(\frac{\sqrt 2}{2})$ $\sin15^{\circ} =(\frac{\sqrt 6}{4})-(\frac{\sqrt 2}{4})$ $\sin15^{\circ} =(\frac{\sqrt 6 - \sqrt 2}{4})$