Anonymous
Anonymous asked in 科學數學 · 1 decade ago

急~~橢圓形切割後的類半橢圓型面積怎麼求?

我想算切割後的類半橢圓型面積,

可是都無從下手,

不知大家有甚麼看法

拜託

P.S.我是國二資優班難一點沒關係

Update:

例如:

長軸為10橫軸為8,

對切怎麼算?

注意:不要給我公式再/2

謝謝

1 Answer

Rating
  • 興豪
    Lv 5
    1 decade ago
    Favorite Answer

    圖片參考:http://imgcld.yimg.com/8/n/AB00229006/o/1510042307...

    y軸左側部份,即橢圓方程式在 x ≤ 0 的部份

    註:(如果看不清楚請下載到桌面上)

    2010-04-24 22:52:33 補充:

    長軸 2a = 10 , a = 5

    短軸 2b = 8 , b = 4

    ∵ a^2x^2 + b^2y^2 = a^2b^2

    ( 長軸平行y軸 )

    ∴ 25x^2+16y^2 = 400

    s.t x^2/16 + y^2/25 = 1

    x^2 = 16 - y^2/25

    x = - sqrt 16-y^2/25

    x ≤ 0

    2010-04-24 22:58:16 補充:

    長軸 2a = 10 , a = 5

    短軸 2b = 8 , b = 4

    a^2x^2 + b^2y^2 = a^2b^2

    (長軸平行y軸)

    25x^2+16y^2 = 400

    x^2/16 + y^2/25 = 1

    x^2 = 16 - y^2/25

    x = - sqrt 16 - y^2/25

    x ≤ 0

    取 y軸左半邊的 橢圓

    2010-04-24 22:59:31 補充:

    長軸 2a = 10 , a = 5

    短軸 2b = 8 , b = 4

    a^2x^2 + b^2y^2 = a^2b^2

    (長軸平行y軸)

    25x^2+16y^2 = 400

    x^2/16 + y^2/25 = 1

    x^2 = 16 - y^2/25

    x = - sqrt 16 - y^2/25

    x ≤ 0

    取 y軸左半邊的 橢圓

    Source(s): 以圖代字
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