Ullman (TOC) Edition 3 Exercise 9.3 Question 6 (Page No. 400)

Question

Show that the following questions are decidable:

1. The set of codes for $TM's \ M$ such that when started with blank tape will eventually write some nonblank symbol on its tape. Hint: If $M$ has $m$ states, consider the first $m$ transitions that it makes.
2. The set of codes for $TM's$ that never make a move left on any input.
3. The set of pairs $(M,w)$ such that $TM \ M$, started with input $w$, never scans any tape cell more than once.