## Trigonometry 7th Edition

Given expression = $\sin^{2} 60^{\circ} + \cos^{2} 60^{\circ}$ = $( \sin 60^{\circ})^{2} + ( \cos 60^{\circ})^{2}$ = $(\frac{\sqrt 3}{2})^{2} + (\frac{1}{2})^{2}$ ( substituting for exact values of $\sin 60^{\circ}$ and $\cos 60^{\circ})$ =$\frac{3}{4} + \frac{1}{4}$ = $\frac{(3+1)}{4}$ = $\frac{4}{4}$ = 1