Formula_9426

\[\varphi^{\mathrm{IV}}-2 \alpha^{2} \varphi^{\prime \prime}+\alpha^{4} \varphi=i \alpha \operatorname{Re}\left\{(\omega-c)\left(\varphi^{\prime \prime}-\alpha^{2} \varphi\right)-\omega^{\prime \prime} \varphi\right\}\]