PUC Karnataka Science Class 12Department of Pre-University Education, Karnataka
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# Solution for Show that the Following Set of Curve Intersect Orthogonally X3 − 3xy2 = −2 and 3x2y − Y3 = 2 ? - PUC Karnataka Science Class 12 - Mathematics

#### Question

Show that the following set of curve intersect orthogonally x3 − 3xy2 = −2 and 3x2y − y3 = 2 ?

#### Solution

$\text { Let the given curves intersect at }\left( x_1 , y_1 \right)$

$x^3 - 3x y^2 = - 2 . . . \left( 1 \right)$

$3 x^2 y - y^3 = 2 . . . \left( 2 \right)$

$\text { Differentiating (1) w.r.t.x,}$

$3 x^2 - 3 y^2 - 6xy\frac{dy}{dx} = 0$

$\Rightarrow \frac{dy}{dx} = \frac{3 x^2 - 3 y^2}{6xy} = \frac{x^2 - y^2}{2xy}$

$\Rightarrow m_1 = \left( \frac{dy}{dx} \right)_\left( x_1 , y_1 \right) = \frac{{x_1}^2 - {y_1}^2}{2 x_1 y_1}$

$\text { Differenntiating (2) w.r.t.x, }$

$3 x^2 \frac{dy}{dx} + 6xy - 3 y^2 \frac{dy}{dx} = 0$

$\Rightarrow \frac{dy}{dx}\left( 3 x^2 - 3 y^2 \right) = - 6xy$

$\Rightarrow \frac{dy}{dx} = \frac{- 6xy}{3 x^2 - 3 y^2} = \frac{- 2xy}{x^2 - y^2}$

$\Rightarrow m_2 = \left( \frac{dy}{dx} \right)_\left( x_1 , y_1 \right) = \frac{- 2 x_1 y_1}{{x_1}^2 - {y_1}^2}$

$\text { Now,} m_1 \times m_2 = \frac{{x_1}^2 - {y_1}^2}{2 x_1 y_1} \times \frac{- 2 x_1 y_1}{{x_1}^2 - {y_1}^2}$

$\Rightarrow m_1 \times m_2 = - 1$

$Since, m_1 \times m_2 = - 1$

So, the given curves intersect orthogonally.

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#### Video TutorialsVIEW ALL [3]

Solution Show that the Following Set of Curve Intersect Orthogonally X3 − 3xy2 = −2 and 3x2y − Y3 = 2 ? Concept: Tangents and Normals.
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