Determine the union of intervals A=[-1,1], B=(0,2] and C=(3,5].
A \cup B \cup C=[-1,1] \cup(0,2] \cup(3,5]=[-1,0) \cup(3,5]
A \cup B \cup C=[-1,1] \cup(0,2] \cup(3,5]=[-1,2] \cup(3,5]
A \cup B \cup C=[-1,1] \cup(0,2] \cup(3,5]=[-1,1] \cup(3,5]
A \cup B \cup C=[-1,1] \cup(0,2] \cup(3,5]=[-1,2] \cup(2,5]
