regular-expression Definition and 1 Threads

I was studying the given finite automata. Using $$R_{ij}^{(k)}$$ method, I found out that the Regular Expression that this automaton accepts is $$R^*S(U+TR^*S)^*$$. But my book says, the regular expression for the accepted strings can be described in various ways. One is $$(R+SU^*T)SU^*$$. How...