20/03/13 17:34:44 l20VjRfO.net
3(x+y)/2 - 2 = 1 - (3/2)/(tt-t+1),
x-y = (2t-1)/(tt-t+1),
より
3(xx +xy +yy -2x -2y +1) +1
= 3{(x-2/3)^2 + (x-2/3)(y-2/3) + (y-2/3)^2}
= {3(x+y)/2 -2}^2 + (3/4)(x-y)^2
= 1,
長半径 a=√(2/3), 短半径 b=(√2)/3, 面積 πab = 2π/(3√3).
20/03/13 17:34:44 l20VjRfO.net
3(x+y)/2 - 2 = 1 - (3/2)/(tt-t+1),
x-y = (2t-1)/(tt-t+1),
より
3(xx +xy +yy -2x -2y +1) +1
= 3{(x-2/3)^2 + (x-2/3)(y-2/3) + (y-2/3)^2}
= {3(x+y)/2 -2}^2 + (3/4)(x-y)^2
= 1,
長半径 a=√(2/3), 短半径 b=(√2)/3, 面積 πab = 2π/(3√3).