 It may be reflected ("A"←) or transmitted ("B"→).Here and in the following assume "E" > "V"0.To find the amplitudes for reflection and transmission for incidence from the left, we set in the above equations "A"→ = 1 (incoming particle), "A"← = (reflection), "B"← = 0 (no incoming particle from the right) and "B"→ = (transmission ).