p. 354
9.2(c): ( q0,
w )
*
( h,
wwr ),
where wr is the reversal of w. The transition diagram of this Turing machine is as follows:
Give a string w this Turing machine copies it from its right end to the leftone by one and writes it from left to righ on the tape to the right of w. At the same time it shifts w to the right one position. As a result wwr is produced.
9.40(a): If the length of every string in the language is at most n, then the language is finite. Hence it is regular. If there are strings longer than n, then this machine does not distinguish strings that differ after the n-th position. Hence the equivalence classes of I L of Corollary 5.1 on p. 171 is finite. Hence the language is regular. (You need to go to pp. 168 - 169 for the definition and explanation of IL).