## Trigonometry (11th Edition) Clone

$\theta = 135^{\circ}$ $\theta = 315^{\circ}$
$cot ~\theta = -1$ $\frac{x}{y} = -1$ We can let $x = -1$ and $y = 1$, or we can let $x = 1$ and $y = -1$ Since $x$ and $y$ have the same magnitude, the angle $\alpha$ above or below the x-axis is $45^{\circ}$. When $x = -1$ and $y = 1$: $\theta = 180^{\circ} - \alpha$ $\theta = 180^{\circ} - 45^{\circ}$ $\theta = 135^{\circ}$ When $x = 1$ and $y = -1$: $\theta = 360^{\circ} - \alpha$ $\theta = 360^{\circ} - 45^{\circ}$ $\theta = 315^{\circ}$