Check the picture below.
[tex]\textit{using the pythagorean theorem} \\\\ c^2=a^2+b^2\implies c=\sqrt{a^2 + b^2} \qquad \begin{cases} c=hypotenuse\\ a=\stackrel{adjacent}{-4}\\ b=\stackrel{opposite}{-5}\\ \end{cases} \\\\\\ c=\sqrt{(-4)^2 + (-5)^2}\implies c=\sqrt{41} \\\\[-0.35em] ~\dotfill[/tex]
[tex]cos(\theta )\implies \cfrac{\stackrel{adjacent}{-4}}{\underset{hypotenuse}{\sqrt{41}}}\implies \cfrac{-4}{\sqrt{41}}\cdot \cfrac{\sqrt{41}}{\sqrt{41}}\implies -\cfrac{4\sqrt{41}}{41} \\\\\\ sec(\theta )\cfrac{\stackrel{hypotenuse}{\sqrt{41}}}{\underset{adjacent}{-4}}\implies -\cfrac{\sqrt{41}}{4}~\hfill cot(\theta )\implies \cfrac{\stackrel{adjacent}{-4}}{\underset{opposite}{-5}}\implies \cfrac{4}{5}[/tex]
