so hmm notice the picture below
that's (0, -3)
now, keep in mind, adjacent is 0, opposite is -3, and hypotenuse, or radius, is 3
and recall [tex]sin(\theta)=\cfrac{opposite}{hypotenuse}
\qquad \qquad
% cosine
cos(\theta)=\cfrac{adjacent}{hypotenuse}
\\ \quad \\\\
% tangent
tan(\theta)=\cfrac{opposite}{adjacent}
\qquad \qquad
% cotangent
cot(\theta)=\cfrac{adjacent}{opposite}
\\ \quad \\
% cosecant
csc(\theta)=\cfrac{hypotenuse}{opposite}
\qquad \qquad
% secant
sec(\theta)=\cfrac{hypotenuse}{adjacent}[/tex]
