TeX source:

=\dfrac{1}{T}[(cr_1−c_r)p_mT_s−\dfrac{h_r}{2}(\dfrac{p^{2}_{m}T^{2}_{s}}{D_c}−2np_mT_sT_R−(2n+1)T_RD_R) \\ +\dfrac{nc_{r+1}i_eD_cM^2}{2}+ \dfrac{c_{r_1}{i_e}}{2} (p_mT_s−nD_R)(2M−T′) \\ −\dfrac{nc_rI_p}{2}[T_RD_R+D_cM_2−2MD_R]−id_rT_R−A_r]