$($COMPUTER$)$Use subroutine RTCOEF $($Appendix D$)$ to tabulate the amplitude and phase of reflected and transmitted waves for downgoing P waves incident on the core$$mantle boundary. Use PREM values $($Appendix A$)$ for the velocities and densities across the interface. Plot your results as a function of ray incidence angle. Note: RTCOEF is for a solid$$solid boundary condition and will blow up for a fluid$$solid boundary. To get around this, use a very small, but non$-$zero, value for the outer core shear velocity. Ignore the result that you obtain for the transmitted shear wave; it should contain very little energy.