Oscillation And Nonoscillation Of Forced Nonlinear Forth Order Differential Equations With Delayed Argument

For a special class of external force g(t)and nonnegative potential a(t).we give necessary conditions for the oscillation and nonoscillation of a nonlincar forth order forced differential equation withdelayed argument of type in the formin the superlincar (β>1)and the sublincar (β<1)and the nonlincar cases.