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MHT CET202016 Oct 2020Morning ShiftMathematicsDifferentiationActual

If x y + y x =4 , then d y d x =

Options

  1. Ay-7 x 7 x-y
  2. B7 y-7 x y-7 x
  3. C7 x+y x-7 y
  4. Dy+7 x 7y-x

Correct answer

B. 7 y-7 x y-7 x

Step-by-step solution

(B) Given : x y + y x =4 x+y x y =4 x+y=4 x y Squaring both sides, we get, (x+y)²=16 x y x²+y²=14 x y Differentiating both sides w.r.t. x array l 2 x+2 y d y d x =14 [x d y d x +y ] x+y d y d x =7 x d y d x +7 y (y-7 x) d y d x =7 y-x d y d x = 7 y-x y-7 x array

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