Question

What is `cot((7pi`/2)#?

Answer 1

`cot((7pi)/2) = 0`

Note that `(7pi)/2 " is the same angle as " (3pi)/2`

Based on a unit circle centered at the origin of the Cartesian plane an angle, `theta`, may be specified by a point `(x,y)` on the circle.
In which case:
`cot(theta) = x/y`

As can be seen by the diagram below that implies
`cot((7pi)/2) = 0/1 = 0`