Q108 / 160 · TS EAMCET 2024 (10 May Shift 1) · Mathematics
The equation of the normal drawn to the curve $y^3=4 x^5$ at the point $(4,16)$ is
- A$20 x+3 y=128$
- B$20 x-3 y=32$
- C$3 x-20 y+308=0$
- Correct answerD$3 x+20 y=332$
Solution
$y^3=4 x^5 \Rightarrow \frac{d y}{d x}=\frac{20 x^4}{3 y^2} \Rightarrow\left(\frac{d y}{d x}\right)_{(4,16)}=\frac{20}{3}$ Slope of normal $=\frac{-3}{20}$
Equation of normal at $(4,16)$ and slope $\frac{-3}{20}$ is
$y-16=\frac{-3}{20}(x-4) \Rightarrow 3 x+20 y=332$
Hence, the correct answer is option: 'D'.