[問題] 解常微分方程

看板Mathematica作者 (青澀的柿子)時間11年前 (2013/03/12 02:47), 編輯推噓3(305)
留言8則, 1人參與, 最新討論串1/2 (看更多)
我要解一個聯立微分方程: x'=0.02x-0.00004xy y'=0.0004xy-0.04y x(0)=500 y(0)=200 其中x,y都是t的函數,我輸入下面的指令: DSolve[{x'[t] == 2/100 x[t] - 4/100000 x[t] y[t], y'[t] == 4/10000 x[t] y[t] - 4/100 y[t], y[0] == 200, x[0] == 500}, {x[t], y[t]}, t] 卻發現電腦給我一大堆錯誤訊息, 想請問是哪裡出了問題?謝謝大家。 -- ※ 發信站: 批踢踢實業坊(ptt.cc) ◆ From: 140.112.55.100

03/13 13:54, , 1F
Solve::ifun: Inverse functions are being used by
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03/13 13:55, , 2F
Solve, so some solutions may not be found; use
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03/13 13:56, , 3F
Reduce for complete solution information. (出現三次)
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03/13 13:56, , 4F
General::stop: Further output of Solve will be
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03/13 13:57, , 5F
suppressed during this calculation.
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03/13 13:58, , 6F
DSolve::bvnul: For some branches of the general
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solution, the given boundary conditions lead to
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03/13 13:59, , 8F
an empty solution. (出現兩次)
03/13 13:59, 8F
文章代碼(AID): #1HFYR5so (Mathematica)
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文章代碼(AID): #1HFYR5so (Mathematica)