Answer
13a. undefined
13b. 0
Work Step by Step
13a. $tan \frac {5\pi} {2}$ is equivalent to $tan \frac {\pi} {2}$ (when $2\pi$ is subtracted from $ \frac {5\pi} {2}$)
This value is undefined.
13b. $cot \frac {5\pi} {2}$ is 0 (since $cos \frac {5\pi} {2}$ is 0 and $sin \frac {5\pi} {2}$ is 0, and cotangent is cosine divided by sine)
