The value of $c$ such that the straight line joining the points $(0,3)$ and $(5,-2)$ is tangent to the curve…

The value of $c$ such that the straight line joining the points $(0,3)$ and $(5,-2)$ is tangent to the curve $y=\frac{c}{x+1}$ is
  1. 3
  2. 4
  3. 5
  4. 2

Solution

Equation of line joining $(0,3)$ and $(5,-2)$ is $\begin{aligned} & \frac{y-3}{x}=-1 \Rightarrow x+y-3=0 ...(i)\\ & \because y=\frac{c}{x+1} \Rightarrow \frac{d y}{d x}=\frac{-c}{(x+1)^2}=-1 \\ & c=(x+1)^2 \\ & y=x+1 \Rightarrow x-y+1=0...(ii) \end{aligned}$
Solving (i) and (ii), $x=1, y=2$
$c=(x+2)^2=4$

Asked in: AP EAMCET 2024 (21 May Shift 2)

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