  It should be regarded that the confirmation of the maximum oscillation in
neutrino oscillation through L/E analysis by Super-Kamiokande is a logical
consequence of their establishment on the existence of neutrino oscillation
through the analysis of the zenith angle distribution for atmospheric neutrino
events. In the present paper (Part1) with the computer numerical experiment, we
examine the assumption made by Super-Kamiokande Collaboration that the
direction of the incident neutrino is approximately the same as that of the
produced lepton, which is the cornerstone in their L/E analysis, and we find
this approximation does not hold even approximately. In a subsequent paper
(Part2), we apply the results from Figures 16, 17, 18 and 19 to L/E analysis
and conclude that one cannot obtain the maximum oscillation in L/E analysis in
the single ring muon events due to quasi-elastic scattering reported by
Super-Kamiokande which shows strongly the oscillation pattern from the neutrino
oscillation.
