undefined equation.

sin (pi/2 – x) = cos x (supplementary arc)

##cot (pi/2 + x) = (cos (pi/2 + x))/(sin (pi/2 + x)) = sin x/(-cos x).##

The left side of the equation simplifies to:

##(cos x)(sin x/(-cos x)) = – sin x##

Then the equation reduces to:

-sin x = – sin x

The equation is undefined. It is insolvable.