Find the slope of tangent line to the curve at the point $(1, \pi/2)$
the equation is $$\sin(xy) = x$$
The right answer was = Slope is infinite
My answer was taking the derivative and I end up in this equation
$$ (1-y\cos(xy))/ x\cos(xy) $$
I substitute with the points and the calculator showed an error, Does the error means infinite ?