Math Chapter Wise Tangent, Normal, Increasing, Decreasing And Maxima/Minima Of A Function Of One Variable English MCQ PGT 2011 Q.If x y x y 2 2 2 + + + = + = then dy dx is equal to: Ax y 2 2 + − Bx y 2 2 1 2 + + Cy x y x 1 2 1 2 − − − Dx y x y 2 2 2 + − Show answer Correct answer: y x y x 1 2 1 2 − − −