0
$\begingroup$

The equation of a curve is $$3x^2 + 8xy + y^2 = -13.$$ Find the equations of the two tangents which are parallel to the $y$-axis.

  • 0
    You've tagged the problem "implicit differentiation." Do you know how to do implicit differentiation? Or is that the bit you can't do?2012-08-09
  • 0
    Well I managed to find dy/dx in terms of x and y, but what do i do from there? dy/dx is a tangent, isn't it?2012-08-09
  • 0
    $dy/dx$ is the *slope* of the tangent line. You're looking for places where that slope is infinite. This will probably correspond to points where your formula for $dy/dx$ results in dividing by zero.2012-08-09

2 Answers 2