text: derive the formula of the area of the ellipsee? this one is for mikenehme funny, i was just gonna say evaluate the integral of   b/a * sqrt(a^2 - x^2)  from x = 0 to x = a and multiply by 4.   (fyi, that's y when you solve x^2/a^2 + y^2/b^2 = 1 in quadrant 1)