silemus.

16Implicit differentiation, folium

The curve x3+y3=6xy\displaystyle x^3 + y^3 = 6xy passes through (3,3)\displaystyle (3, 3). Find dydx\displaystyle \frac{dy}{dx} at that point.

Differentiate both sides with respect to x, using the chain rule on y³ and the product rule on 6xy. Solving for dy/dx gives (6y−3x²)/(3y²−6x), and at (3,3) this equals −1.

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