Interval Notation for Set Intersection and Union

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rudders93
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Homework Statement


Consider the following intervals:

A = [-3,5), B = (3,8), C = (0,4]

Find: A[itex]\cap[/itex]B and A[itex]\cap[/itex]C

The Attempt at a Solution



I thought that: A[itex]\cap[/itex]B=(3,5) and that A[itex]\cap[/itex]C=[0,4] as that is the intersection point, but this book (Schaum's Probability Outlines) says that A[itex]\cap[/itex]B=[-3,8) and A[itex]\cap[/itex]C=[-3,5)

I'm looking to confirm that the book might be wrong (Amazon reviews indicate a lot of typographical errors) and instead maybe their answer refers to [itex]A\cup B[/itex] and [itex]A\cup C[/itex] perhaps? Or am I getting confused?

Thanks!
 
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The book answers are for union [itex]\cup[/itex], and you are really close to correct with your answers for intersection [itex]\cap[/itex]. It could be a typo in either question or answer.
 
Yes, [itex]A\cap B= (3, 5)[/itex] while [itex]A\cup B= [-3, 8)[/itex] as Joffan says. [itex]A\cup C= [-3, 5)[/itex]. But [itex]A\cap C[/itex] is NOT [0, 4] because 0 is not in C.
In fact, C is a subset of A so [itex]A\cap C= C[/itex] and [itex]A\cup C= A[/itex].