## Trigonometry (11th Edition) Clone

$x=-1$
Subtract $4\pi$ to both sides: $-4\cot^{-1}{(x)}=-3\pi$ Divide $-4$ to both sides: $\cot^{-1}{(x)}=\frac{-3\pi}{-4} \\\cot^{-1}{(x)}=\frac{3\pi}{4}$ RECALL: $\cot^{-1}{(x)} = \theta \longrightarrow \cot{\theta} = x$ Use the rule above to obtain: $\cot^{-1}{(x)} = \frac{3\pi}{4} \\\cot{(\frac{3\pi}{4})}=x \\-1=x$