Answer
$y'=-6x\csc^{2}(3x^{2}+5)$
Work Step by Step
$y=\cot(3x^{2}+5)$
Start the differentiation process by using the chain rule:
$y'=-(3x^{2}+5)'\csc^{2}(3x^{2}+5)=...$
Evaluate the indicated derivative and simplify:
$...=-6x\csc^{2}(3x^{2}+5)$