I think you meant "y = 4 arccot (x)."
This is equivalent to:
y
---- = arccot x
4
and so cot (y/4) = x
It does show a function because it passes the vertical line test (no two points have the same x value).
We use the pythagorean theorem and information about the rectangular prism to find the length of the hypotenuses that the spider walks along. Adding them together (5.39+5+5.83+3.91) gives us 20.13cm, the answer.
