If \(f = \text{Tan}^{-1}(xy)\) then \((\frac{\partial f}{\partial x})_{(1,2)}\) = _____ .
\(P(A) = \frac{1}{3}\), \(P(B) = \frac{3}{4}, P(A \cap B) = \frac{1}{6}\), then probability of \( A \) alone is