Answer
$3.11448036786$
Work Step by Step
Make sure that the setting for angles is "radians".
$\cot^{-1}x$ is evaluated as $\left\{\begin{array}{lll}
\tan^{-1}(1/x) & if & x > 0\\
\pi+\tan^{-1}(1/x) & if & x <0
\end{array}\right.$
(x is negative here)
Keys:
"shift" or "2nd function"
"tan"
numerical keypad: ($-1\div$36.874610)
"="
numerical keypad: $+\pi$
"="
yields
$3.11448036786$
