TeX source:

R(x, y)=\left(c_{h}+\alpha c_{1}\right)\left[\frac{p}{\alpha^{2}} \log \left\{1+\frac{\alpha}{p} \int_{x}^{y} e^{\alpha(t-x)} D(t) d t\right\}-\frac{1}{\alpha} \int_{x}^{y} D(t) d t\right]