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
- $\frac{-17}{4}$
- $\frac{4}{17}$
- $\frac{-4}{17}$
- $\frac{17}{4}$
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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