How can we combine or merge two deterministic finite automata (DFAs) to create a new DFA that represents the union of the two original DFAs?

To combine two deterministic finite automata (DFAs) to create a new DFA representing their union, you can merge the two DFAs by adding a new start state connected to the original start states of the two DFAs with epsilon transitions. This new DFA will accept a string if either of the original DFAs would accept that string.