请教 这个方程

snower1895

这个方程的解法有问题吗  怎末电脑一直Running 就是不出结果 是太复杂了吗
d = 16
h = 4.91
t = 11
k = 2 pi/l
s = Sinh[k d]
c = Cosh[k d]
l0 = 9.8 t^2/(2 pi)
B33 = 3 (8 c^6 + 1)/(64 s^6)
B35 = (88128 c^14 - 20822 c^12 + 70848 c^10 + 54000 c^8 - 21816 c^6 +
    6264 c^4 - 54 c^2 - 81)/(12288 s^12 (6 c^2 - 1))
B55 = (192000 c^16 - 26270 c^14 + 83680 c^12 + 20160 c^10 -
     7280 c8)/(12288 s^10 (6 c^2 - 1) (8 c^4 - 11 c^2 +
       3)) + (7160 c^6 - 1800 c^4 - 1050 c^2 +
     225)/(12288 s^10 (6 c^2 - 1) (8 c^4 - 11 c^2 + 3))
c1 = (8 c^4 - 8 c^2 + 9)/(8 s^4)
c2 = (3840 c^12 - 4096 c^10 + 2592 c^8 - 1008 c^6 + 5944 c^4 -
    1830 c^2 + 147)/(512 s^10 (6 c^2 - 1))
fi = pi h/d ==
  l/d (\[Lambda] + \[Lambda]^3 B33 + \[Lambda]^5 (B35 + B55))
fj = d/l0 == d/l Tanh[k d] (1 + \[Lambda]^2 c1 + \[Lambda]^4 c2)
Solve[{fi, fj}, {l, \[Lambda]}]


其中的\【lambda】是一个变量  copy导致的变形

FreddyMusic

you can use some forum code to have a better quality post and avoid information misunderstanding.

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ryan_xu

pi-> Pi ?
c8->c^8 ?