[問題]聯立方程式求解問題

看板Mathematica作者huarache (~絮~)時間11年前 (2013/04/30 18:09)推噓0(0推 0噓 1→)

留言1則, 1人參與討論串1/1

eqn9 = (-Cos[s3] Dt[r3, t] - r2 Dt[s2, t] Sin[s2] + r3 Dt[s3, t] Sin[s3] == 0) eqn10 = (r2 Cos[s2] Dt[s2, t] - r3 Cos[s3] Dt[s3, t] - Dt[r3, t] Sin[s3] == 0) eqn11 = (-Dt[r6, t] - r4 Dt[s3, t] Sin[s3] - r5 Dt[s5, t] Sin[s5] == 0) eqn12 = (r4 Cos[s3] Dt[s3, t] + r5 Cos[s5] Dt[s5, t] == 0) => eqn13 = Eliminate[{eqn9, eqn10}, Dt[r3, t]] => r3 Cos[s3]^2 Dt[s3, t] - r2 Dt[s2, t] Sin[s2] Sin[s3] + r3 Dt[s3, t] Sin[s3]^2 == r2 Cos[s2] Cos[s3] Dt[s2, t] (Solve[eqn13, Dt[s3, t]][[1, 1]] // FullSimplify) /. Rule -> Equal => Dt[s3, t] == (r2 Cos[s2 - s3] Dt[s2, t])/r3 eqn14 = (-r4 Dt[s3, t] Sin[s3] - r5 Dt[s5, t] Sin[s5] == Dt[r6, t]) => eqn15 = Eliminate[{eqn12, eqn14}, Dt[s5, t]] => r4 Dt[s3, t] (-Cos[s5] Sin[s3] + Cos[s3] Sin[s5]) == Cos[s5] Dt[r6, t] eqn100 = (Solve[eqn15, Dt[r6, t]] //. {s5 -> ArcSin[(r7 - r4 Sin[s3])/r5], s3 -> ArcTan[(r1 + r2 Sin[s2])/(r2 Cos[s2])], Dt[s3, t] -> (r2 Cos[s2 - s3] Dt[s2, t])/r3} // FullSimplify) /. Rule -> Equal => 很大一串 eqn100 /. {r1 -> 220.73, r2 -> 85, s2 -> \[Pi]/2, Dt[s2, t] -> 8.968, r3 -> 305.73, r4 -> 535.275, r5 -> 175, r7 -> 535.275} => 如果沒輸入s2->pi/2，方程式就會剩一個s2變數如果輸入s2->pi/2，則會跑出{{Dt[r6, t] == Indeterminate}} 想請問是我哪邊出了問題嗎? 謝謝抱歉我PTT也是新手，不太會用色碼標記s2部分QQ -- ※ 發信站: 批踢踢實業坊(ptt.cc) ◆ From: 140.124.33.168 ※ 編輯: huarache 來自: 140.124.33.168 (04/30 18:11)