Answer:
theta might increase in this way because inflation expectations adapt to persistently positive inflation.
Step-by-step explanation:
Since every year inflation rate is 6% , rather then expected inflation according to formula, 3%
Thus inflationary expectations should incorporate the higher inflation rate, so adaptive expectations follow :
In year t + 6 : 10%
t + 7 : 14%
t + 8 : 18%