The slope of the normal to the curve $x=\sqrt{t}$ and $y=\mathrm{t}-\frac{1}{\sqrt{\mathrm{t}}}$ at…

The slope of the normal to the curve $x=\sqrt{t}$ and $y=\mathrm{t}-\frac{1}{\sqrt{\mathrm{t}}}$ at $\mathrm{t}=4$ is
  1. $\frac{-17}{4}$
  2. $\frac{4}{17}$
  3. $\frac{-4}{17}$
  4. $\frac{17}{4}$

Solution

$\begin{aligned} & \frac{\mathrm{d} y}{\mathrm{~d} x}=\frac{\frac{\mathrm{d} y}{\mathrm{dt}}}{\frac{\mathrm{d} x}{\mathrm{dt}}}=\frac{1+\frac{1}{2 \mathrm{t}^{\frac{3}{2}}}}{\frac{1}{2 \sqrt{\mathrm{t}}}}=\frac{2 \mathrm{t}^{\frac{3}{2}}+1}{\mathrm{t}} \\ \therefore \quad\left(\frac{\mathrm{d} y}{\mathrm{~d} x}\right)_{\mathrm{t}=4}= & \frac{2(4)^{\frac{3}{2}}+1}{4}=\frac{16+1}{4}=\frac{17}{4} \end{aligned}$ $\therefore \quad$ Slope of normal at $\mathrm{t}=4$ is $-\frac{1}{\left(\frac{\mathrm{d} y}{\mathrm{~d} x}\right)_{t=4}}=-\frac{4}{17}$

Asked in: MHT CET 2023 (13 May Shift 1)

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