The equation of normal to the curve $2 x^{2}+3 y^{2}-5=0$ at $P(1,1)$ is
The equation of normal to the curve $2 x^{2}+3 y^{2}-5=0$ at $P(1,1)$ is
- $3 x+2 y+1=0$
- $3 x-2 y+1=0$
- $3 x+2 y-5=0$
- $3 x-2 y-1=0$
Solution
Given $2 x^{2}+3 y^{2}-5=0$
$4 x+6 y \frac{d y}{d x}=0 \Rightarrow \frac{d y}{d x}=\frac{-2 x}{3 y}$
$\operatorname{At}(1,1), \quad \frac{\mathrm{d} y}{\mathrm{dx}}=\frac{-2}{3} \Rightarrow$ Slope of normal $=\frac{3}{2}$ Equation of normal is
$\begin{aligned}
& y-1=\frac{3}{2}(x-1) \Rightarrow 2 y-2=3 x-3 \\
\therefore \quad & 3 x-2 y-1=0
\end{aligned}$
Asked in: MHT CET 2020 (15 Oct Shift 1)
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