Equation Icon  hν hν x (x − 1 ) x = ---2, xc = ---c2, η1 = --2--1-----, mec mec 1 − x1x2 x = 1 + 4𝜃 + 16𝜃2, η = −-η1, 1 e e 2 3η3 x2 = 1 − exp (− τes), η3 = − 1 − lnx2∕ ln x1, (79 )