1. The problem statement, all variables and given/known data 7 Find the points on the ellipse x^2 + 2y^2 = 1 where the tangent line has slope 1 2. Relevant equations 3. The attempt at a solution I got the correct X and Y values but this gives me four possibilities and the answer key says there are two points. I got x = +/- sqrt 2/3 and y = +/- sqrt 1/6 The values are correct but how am I supposed to know which coordinate to pare with which? For an example, how do I know if it's (-sqrt 2/3, -sqrt 1/6) or (sqrt 2/3, -sqrt 1/6) ?