Math Chapter Wise Ordinary And Partial Differential Equations, Integral Equations And Calculus Of Variations English MCQ UP PCS (Pre) 1996 Q.The differential equation P dx + Q dy = 0 is exact, if: A2 P x y ∂ − ∂ ∂ = 0 BaP Q x y ∂ = ∂ ∂ CP Q y x ∂ ∂ = ∂ ∂ DNone of these Show answer Correct answer: P Q y x ∂ ∂ = ∂ ∂