We examine the equations of motion of double field theory and the duality
manifest form of M-theory. We show the solutions of the equations of motion
corresponding to null pp-waves correspond to strings or membranes from the
usual spacetime perspective. A Goldstone mode analysis of the null wave
solution in double field theory produces the equations of motion of the duality
manifest string.Comment: 31 pages, LaTex, v2 some typos corrected and refs adde