Eq. (4.11): $\mathrm{Re}\big[-\int_{-\infty}^0 i\frac{d\eta}{\eta^2}\prod_j(1-ik_j\eta)e^{ik_t\eta}\big] = -k_t+\frac{\sum_{i>j}k_ik_j}{k_t}+\frac{k_1k_2k_3}{k_t^2}$

Initializing...

Eq. (4.11): $\mathrm{Re}\big[-\int_{-\infty}^0 i\frac{d\eta}{\eta^2}\prod_j(1-ik_j\eta)e^{ik_t\eta}\big] = -k_t+\frac{\sum_{i>j}k_ik_j}{k_t}+\frac{k_1k_2k_3}{k_t^2}$ · Prove2Me