4. The transition diagram for Question 2 was:
a) i) The string 01 would leave the automaton in the state
t2.
ii) The string 0010 would leave the automaton in the state t1.
iii) The string 11000 would leave the automaton in the state t3.
iv) The string 111 would leave the automaton in the state t2.
b) From part a), the strings 01 and 111 send the automaton to an accepting state.
c) You are looking for all the strings which will cause you to finish in the state t2. If we examine which input values will send the automaton to the state t2 for each of the three states, we see that in each case the input symbol 1 sends the automaton to the state t2 (or keeps it in state t2 if it was already there). Hence the language accepted by this automaton consists of all strings (of length at least one) of 0's and 1's which end in a 1.