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