Find the equation of the tangent to the ellipse x2 + 2y2 = 4 at the p...
Given
Equation of ellipse is x2 + 2y2 = 4
Here, we have to find the equation of the tangent to the given ellipse at the point where ordinate is 1 such that the point lies in the first quadrant.
Let the point be P = (c, 1)
Now this point P lies on the ellipse. So, x = c and y = 1 will satisfy the equation x2 + 2y2 = 4
c/2 + 2 = 4
c = ± √2
So, the point P is (√2, 1) because the point P lies in the first quadrant.
The given equation of ellipse we can be re-written as: (x2/4) + (y2/2) = 1
As we know that, the equation of the tangent to the horizontal ellipse x2/a2 + y2/b2 = 1 where 0 < b="" />< a="" at="" the="" point="" />1, y1) is given by:
So, the required equation of tangent is √2x + 2y - 4 = 0
Hence, the correct option is (D).