Problem $1$: Consider the following languages L$1=\{0,1\},$ L$2=\{01,12,20\}$ and L$3=\{02,21\}$

Let $L_1=\{a\}$ and $L_2=\{b\},$ list all strings of length $2$ that are not from $L_2^{**}{L}_1^{**}($if you

think there are no such strings then explain why$)$

Let $L_1=\{a\}$ and $L_2=\{b\},$ list all strings of length $3$ that are not from $L_1*L_2^{**}($if you

think there are no such strings then explain why$)$

Let $L_1=\{ab,ba\},$ list all strings of length $4$ that are not from $L_1^{**}($if you think there are

no such strings then explain why$)$