How do you implicitly differentiate x^3 - 3xy + 2y^3 = 3x33xy+2y3=3?

1 Answer

dy/dx=(y-x^2)/(2y^2-x)dydx=yx22y2x

Explanation:

We assume that y is a function of x, ie y=f(x)y=f(x) and then differentiate each side of the equation with respect to x, then re-arrange and solve for dy/dxdydx.

d/dx(x^3-3xy+2y^3)=d/dx(3)ddx(x33xy+2y3)=ddx(3)

therefore 3x^2-3xdy/dx-3y+6y^2dy/dx=0. (Used product rule and power rule)

therefore dy/dx(-3x+6y^2)=3y-3x^2. (Took out common factor)

therefore dy/dx=(3y-3x^2)/(6y^2-3x)

therefore dy/dx=(y-x^2)/(2y^2-x) (Divide all by 3).