In a small flip angle COSY experiment, work out the contribution which the operator product 1+ 23,

Question:

In a small flip angle COSY experiment, work out the contribution which the operator product 1+ 2β3α, present during t1, makes to the 1-2 cross peak. You should follow the same approach as used in section 10.4.4 on page 340 for the term 1+ 1α3α
Without further detailed calculations, state the contribution to the 1-2 cross peak made by the term 1- 2β3α.