v 6.1

E_{P} = \int_{Σ} K (θ) \frac{E_{0}}{R r} \exp [i k (R + r)] d Σ

${E_P= \int_\Sigma K(\theta) \frac{E_0}{Rr} \exp[ik(R+r)] \mathrm{d} \Sigma}$

Error