Originally Posted by

**soniadso** Hi,

I'm a bit confused about this implicit differentiation question.

Find the equation of the tangent to the curve 2x^{2 }+ y - xy^{2} - 2y^{3} = 4 at the point (-1, -1).

I am confused because substituting the x and y coordinates into the above equation does not equal to 4. Does this simply mean that the line is not on the curve?

I solved for dy/dx and got (-4x - y^{2}) / (1-x2y-6y^{3}) and substituting (-1, -1) into this equation I got the slope of the tangent to the curve to be y= 1/3 (x+1) -1.

Does this seem right?

Please Help?!

Thank you