Question 1045954
{{{f(x) = 9/(2sin^2(x) - sinx-1) = 9/(( 2sinx+1) ( sinx - 1  ))}}}.

Let 2sinx +1 = 0, or sinx - 1 = 0.

===> sinx = -1/2,  or sinx = 1.

===> {{{x = 7pi/6}}}, {{{x = 11pi/6}}}, or {{{x= pi/2}}}.

These are also the equations for the vertical asymptotes.