KARNATAKA-2nd-PUC-2023-Mathematics-Sample-Paper
KARNATAKA 2nd PUC 2023 Mathematics Sample Paper Question 44
Find the equation of the curve passing through the point (-2, 3), given that the slope of the tangent to the curve at any point $(x, y)$ is $\dfrac{2x}{y^2}$
Solution
The correct answer is $y^3 = 3x^2 + 15$
Explanation
Given that the slope is $\dfrac{2x}{y^2}$
⇒ $\dfrac{dy}{dx}$ = $\dfrac{2x}{y^2}$
⇒ $y^2 dy$ = $2x dx$
Integrating both sides,
⇒ $\int y^2 dy$ = $\int 2x dx$
$\dfrac{y^3}{3}$ = $\dfrac{2x^2}{2}$ + $C_1$
$y^3$ = $3x^2$ + $C$
For the point (-2, 3),
$(-3)^3$ = $3(-2)^2$ + $C$ ⇒ $C$ = $15$
The equation of the curve is $y^3 = 3x^2 + 15$
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