摘要
By means of a simple and direot method,the authors obtain the sharp lower bound ofthe life-span of classioal solutions to the Cauohy problem with small initial data for onedimensional fully nonlinear wave equations u<sub>ti</sub>-u<sub>xx</sub>=F（u,Du,Du<sub>x</sub>）.
By means of a simple and direct method) the authors obtain the sharp lower bound of the life-span of classical solutions to the Cauchy problem with small initial data for one dimensional fully nonlinear wave equations u(tt) - u(xx) = F(u, Du, Du(x)).
