Textbook Problem

Let r, s, and t be regular expressions over $\sum =\left\{a,b\right\}$. In 28—30, determine whether the two regular expressions define the same language. If they do, describe the language. If they do not, give an example of a string that is in one of the languages but not the other.

29. ${\left(rs\right)}^{*}$ and $r^{*}{s}^{*}$