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COMEDK2020MathematicsApplication of Derivatives

The length of the subtangent to the curve x² y²=a⁴ at (-a, a) is

Options

  1. A2 a
  2. Ba / 2
  3. Ca / 3
  4. Da

Correct answer

D. a

Step-by-step solution

We have, aligned &x² y²=a⁴ 2 x y²+x² (2 y y^ )=0 & y^ r = -2 x y² 2 x² y = -y x & . d y d x |_ (-a, a) = -a -a =1 aligned Now, length of subtangent = | y d y / d x |= | a 1 |=a

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