haha
Lv 7
haha asked in 科學數學 · 1 decade ago

微積分之triple integration!

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  • rex
    Lv 7
    1 decade ago
    Favorite Answer

    z的積分區間沒有根號耶

    直接用球座標轉換

    原式=∫∫(9-x^2-y^2)√(x^2+y^2) dxdy, x=rcosθ, y=rsinθ

    =∫∫(9-r^2)r rdrdθ, r:[0,3], θ:[0,pi]

    =∫∫(9r^2-r^4) drdθ

    ={3r^3-(1/5)r^5|[0,3]}{θ|[0,pi]}

    =162pi/5

    2010-06-17 08:31:39 補充:

    應該是圓座標轉換

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