Oscillation Criteria for Third Order Nonlinear Delay Differential Equations with Damping

<p>This note is concerned with the oscillation of third order non-liner delay differential<br>equation of the form<br>                   0<br>/<br>/<br>/<br>/<br>r2<br>t r1<br>t y t  p t y t  q t f y g t  <br>In the papers (A. Tiryaki. M.F Aktas oscillation criteria of a certain class of third order nonliner delay differential equation with damping J .Math Appl 325(2007) 54-68) and (M.f Aktas A.<br>Tiryaki. A. Zafer oscillation criteria for third order non-linear functional differential equation<br>Applied Math. Letter 23 (2010) 756-762)<br>The Authors established some Sufficient conditions Which insure that any solution of equation<br><br>oscillator or converges to Zero. provided that the second order equation<br>        /<br>1<br>    0<br>/<br>/<br>r2<br>t z t  p t r t z t  <br>is non oscillatory. Here we shall improve and unify the result given in the above mentioned<br>papers and present some new sufficient conditions which insure that any solution of equation<br><br>oscillates equation<br><br>is non oscillatory we also establish result for the oscillation of equation<br><br>when equation<br><br>is oscillatory.</p>