Mark M. answered 01/29/23
Retired math prof. Calc 1, 2 and AP Calculus tutoring experience.
An equation of the ellipse is x2 / 49 + y2 /4 = 1
The ellipse has center (0,0), x-intercepts (7,0) and (-7, 0) and y-intercepts (0, 2) and (0,-2).
Solving for y, we get y2 / 4 = 1 - x2 / 49
So, y2 = 4 - 4x2 / 49
y = ±√(4 - 4x2 / 49) = ±2√(1 - x2 / 49)
The portion of the curve that lies in the first quadrant has equation y = 2√(1 - x2/49), where 0 < x < 7. The area of the region bounded by this curve, the x-axis and y-axis is 1/4 of the total area of the ellipse.
So, integrating g(x) = 4y = 8√(1 - x2 / 49) from x = 0 to x = 7 gives the area of the ellipse.