How to Correctly Apply Implicit Differentiation?

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5ymmetrica1
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Homework Statement


For the curve x2+3xy+y2 = 5

show that [itex]\frac{dy}{dx} =- \frac{2x+3y}{3x+2y}[/itex]


Homework Equations



N.A.

The Attempt at a Solution


2x + 3xy + 2y[itex]\frac{dy}{dx}[/itex] = 0

3x + 2y [itex]\frac{dy}{dx}[/itex] = -2x+ 3y

∴ [itex]\frac{dy}{dx} =- \frac{2x+3y}{3x+2y}[/itex]

have I done this correctly?
 
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5ymmetrica1 said:

Homework Statement


For the curve x2+3xy+y2 = 5

show that [itex]\frac{dy}{dx} =- \frac{2x+3y}{3x+2y}[/itex]


Homework Equations



N.A.

The Attempt at a Solution


2x + 3xy + 2y[itex]\frac{dy}{dx}[/itex] = 0

3x + 2y [itex]\frac{dy}{dx}[/itex] = -2x+ 3y

∴ [itex]\frac{dy}{dx} =- \frac{2x+3y}{3x+2y}[/itex]

have I done this correctly?

No. You forgot to differentiate 3xy, or you forgot to write it out, and there are other problems with parentheses.

ehild