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TS EAMCET · Maths · Application of Derivatives

A ladder of length \(13 \mathrm{mts}\) has one end resting against a vertical wall and the other on the ground. If the lower end moves away from the wall at a speed of \(2 \mathrm{mts} /\) minute, then the speed (in \(\mathrm{mts} / \mathrm{min}\) ) at which upper end falls when the bottom is \(5 \mathrm{mts}\) away from the wall is

  1. A \(\frac{6}{5}\)
  2. B \(\frac{12}{5}\)
  3. C \(\frac{5}{6}\)
  4. D \(\frac{5}{12}\)
Verified Solution

Answer & Solution

Correct Answer

(C) \(\frac{5}{6}\)

Step-by-step Solution

Detailed explanation

\(\frac{d x}{d t}=2 \Rightarrow x^2+y^2=169\) \(\begin{aligned} & 2 x \frac{d x}{d t}+2 y \frac{d y}{d t}=0 \\ & \Rightarrow 2 x(2)+2 y\left(\frac{d y}{d t}\right)=0\end{aligned}\) when \(x=5, y=12\)…