駭客數學 p9-24

[acdimns]

x=4cost+1
y=3sint-2
(A)直線 (B)圓 (C)拋物線 (D)橢圓

答:(D)橢圓

[thepiano]

(x - 1)/4 = cost
(y + 2)/3 = sint

(x - 1)^2/4^2 + (y + 2)^2/3^2 = (cost)^2 + (sint)^2 = 1
故為橢圓

[acdimns]

謝謝您!