Formula_15171

\[u(x, t)=4 \operatorname{arctg}\left\{\frac{v}{\mu} \frac{\sin \left[\left(\omega_{1}\left(1-v^{2}\right)^{-1 / 2}\right)\left(t-v x+\varphi_{0}\right)\right]}{\operatorname{ch}\left[\left(\omega_{2}\left(1-v^{2}\right)^{-1 / 2}\right)\left(x-v t-x_{0}\right)\right]}\right\},\]