试了试ToRadicals完全没用呀
Root[-2 E^(2 a)
Cos[p] Sinh[
a] + (Sqrt[2] Sin[2 p] -
Sqrt[2] E^(4 a) Sin[2 p]) #1 + (-4 E^a Cos[3 p] +
4 E^(3 a) Cos[3 p] + 18 E^(2 a) Cos[p] Sinh[a] -
16 E^(2 a) Cos[p] Cosh[2 a] Sinh[a]) #1^2 + (8 Sqrt[2]
Sin[2 p] -
8 Sqrt[2] E^(4 a) Sin[2 p]) #1^3 + (-4 E^a Cos[3 p] +
4 E^(3 a) Cos[3 p] - 268 E^(2 a) Cos[p] Sinh[a] -
16 E^(2 a) Cos[p] Cosh[2 a] Sinh[a]) #1^4 + (14 Sqrt[2]
Sin[2 p] -
14 Sqrt[2] E^(4 a) Sin[2 p]) #1^5 + (4 E^a Cos[3 p] -
4 E^(3 a) Cos[3 p] + 268 E^(2 a) Cos[p] Sinh[a] +
16 E^(2 a) Cos[p] Cosh[2 a] Sinh[a]) #1^6 + (8 Sqrt[2]
Sin[2 p] -
8 Sqrt[2] E^(4 a) Sin[2 p]) #1^7 + (4 E^a Cos[3 p] -
4 E^(3 a) Cos[3 p] - 18 E^(2 a) Cos[p] Sinh[a] +
16 E^(2 a) Cos[p] Cosh[2 a] Sinh[a]) #1^8 + (Sqrt[2] Sin[2 p] -
Sqrt[2] E^(4 a) Sin[2 p]) #1^9 +
2 E^(2 a) Cos[p] Sinh[a] #1^10 &, 2]

10次方程本来也不要指望有什么根式解