Answer
$x=\frac{1}{5}$ $arccot(\frac{y}{3})$
Work Step by Step
$y=3cot5x$
Need to solve $x$ in order to find this divide the above equation by 3 both sides.
$\frac{y}{3}=cot5x$
Apply definition of arccot.
$5x=arccot(\frac{y}{3})$
$x=\frac{1}{5}$ $arccot(\frac{y}{3})$
