[填空题]
The curve C is defi iz)sg nsw 3a1jbzr5w*n9 m .5lnv;ms8pa6jc0e /9 ecifs).kn gabv9*ned by the equation $x^{2} y+\ln (x y)=1$, x $\lt$0, y $\lt$0 .
1. Find $\frac{\mathrm{d} y}{\mathrm{~d} x}$ in terms of x and y .
2. Determine the equation of the tangent to C at the point $\mathrm{P}(1,1)$.
