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MHT CET · Maths · Application of Derivatives

The equation of normal to the curve \(2 x^{2}+3 y^{2}-5=0\) at \(P(1,1)\) is

  1. A \(3 x+2 y+1=0\)
  2. B \(3 x-2 y+1=0\)
  3. C \(3 x+2 y-5=0\)
  4. D \(3 x-2 y-1=0\)
Verified Solution

Answer & Solution

Correct Answer

(D) \(3 x-2 y-1=0\)

Step-by-step Solution

Detailed explanation

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
\(y-1=\frac{3}{2}(x-1) \Rightarrow 2 y-2=3 x-3\)
\(\therefore 3 x-2 y-1=0\)