## Trigonometry (10th Edition)

$\cos$(2 * 45$^{\circ}$) = 2$\cos$ 45$^{\circ}$ First evaluate the value of each trigonometric statement: $\cos$ (2 * 45$^{\circ}$) = $\cos$ 90$^{\circ}$ = 0 $\cos$ 45$^{\circ}$ = $\frac{\sqrt2}{2}$ Next evaluate each side of the equation: $\tan$( 90$^{\circ}$) = 0 2 $\cos$ 45$^{\circ}$ = 2($\frac{\sqrt2}{2}$) = $\sqrt2$ Therefore: $\cos$(2 * 45$^{\circ}$) = 2$\cos$ 45$^{\circ}$ is a false statement.