## Trigonometry 7th Edition

$1$
Given expression is- $\sin^{2} 45^{\circ} + \cos^{2} 45^{\circ}$ = $(\sin 45^{\circ})^{2} + (\cos 45^{\circ})^{2}$ = $(\frac{1}{\sqrt 2})^{2} + (\frac{1}{\sqrt 2})^{2}$ (Substituting exact values) = = $(\frac{1}{2}) + (\frac{1}{2})$ = $1$