Why does Mathematica fail to solve my equation?

Question

I am trying to solve an equation using Mathematica, but I keep getting the following error

Solve::nsmet: This system cannot be solved with the methods available to Solve.

More importantly, it is running for more than half an hour without giving any solution. I have also tried Reduce, but that does not work either.

Any suggestions? How I can fix the error? I am new to Mathematica. My apologies if this is a very basic question.

I am trying to find θ1 (angle)?

x = (e*b*Cos[θ1] + v)^2/(v^2 + e^2*b^2 + 2*e*v*b*Cos[θ1])

Eq2 = a^2 + e*(Sin[θ]- Sin[θ1]) + v/b(θ-θ1)-a*Sqrt[x] == 
   a^2*x + e^2*(Cos[θ]-Cos[θ1])^2- 2*a*e*(Cos[θ]-Cos[θ1])*Sqrt[x]

Solve[Eq2, θ1]

Answer 1

Many classes of equations cannot be solved analytically. If you know the values of your parameters you could use a numerical approach:

Block[{e = 1, b = 2, v = 3, a = 4, θ = 5}, 
 FindRoot[Eq2, {θ1, 1}]
]

{θ1 -> 0.9082966746}