Given that the ellipse x ^ 2 + 2Y ^ 2 = 4 intersects with the straight line L at two points a and B, and the point is the midpoint of (1,1) chord, the equation of the straight line?

Given that the ellipse x ^ 2 + 2Y ^ 2 = 4 intersects with the straight line L at two points a and B, and the point is the midpoint of (1,1) chord, the equation of the straight line?

Let a (x1, Y1), B (X2, Y2), X1 + x2 = 2, Y1 + y2 = 2,
Then X1 ^ 2 + 2y1 ^ 2 = 4, X2 ^ 2 + 2Y2 ^ 2 = 4,
(x1+x2)(x1-x2)+2(y1+y2)(y1-y2)=0,
So (y1-y2) / (x1-x2) = (x1 + x2) / [- 2 (Y1 + Y2)] = - 1 / 2,
The linear equation is Y-1 = - 1 / 2 (x-1), x + 2y-3 = 0