1. The problem statement, all variables and given/known data Find the slope of the tangent line to x tan y = y - 1 when y = pi/4 2. Relevant equations 3. The attempt at a solution I can't seem to get the derivative. Here's what I do. First I used the product rule the left side of the equation and got sec^2 x dy/dx + tan y = dy/dx. When I simplify, I get dy/dy over dy/dx, which just reduces to 1 so I'm having trouble with getting dy/dx on it own.