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WBJEE · Maths · Application of Derivatives

Let \(y=f(x)\) be any curve on the \(X-Y\) plane \& \(P\) be a point on the curve. Let \(C\) be a fixed point not on the curve. The length \(P C\) is either a maximum or a minimum, then

  1. A PC is perpendicular to the tangent at P
  2. B PC is parallel to the tangent at \(P\)
  3. C PC meets the tangent at an angle of \(45^{\circ}\)
  4. D PC meets the tangent at an angle of \(60^{\circ}\)
Verified Solution

Answer & Solution

Correct Answer

(A) PC is perpendicular to the tangent at P

Step-by-step Solution

Detailed explanation

- Let \(P(x, y)\) be a point on the curve, and let \(C(a, b)\) be a fixed point not on the curve. - The distance \(d\) from \(C\) to \(P\) is given by \(d=\sqrt{(x-a)^2+(y-b)^2}\). - To find the extremum, we would set up an optimization problem for \(d\) with respect to the…