Note on Griffiths 9.37
Ignore Griffith's answer to part (d) (his equations 9.203). What
he wants are the transmitted fields, but he has chosen the phase of the
amplitude Eto to be zero, which is not possible in general,
if the incident field amplitude has zero phase-- the usual
assumption. Your (correct) expressions will look a bit more
Proceed with (e) and (f) using the correct fields.