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Question

Here is the question:
Write the set of points from -2 to 4 but excluding -1 and 4 as a union of intervals

my solution to this would be: [-2,4]U(-1,4)
my reasoning:
The first set includes -2 and goes up to and includes 4, the second includes everything greater than -1 and goes to everything less than 4. This way, the integer -2 is still included. BUT, this is wrong.

Answer 1

If you had all the points, you'd have [-2,4]

But, you have to exclude 4, leaving [-2,4)

Now, inside this interval, you exclude -1, so you have to break it up into two intervals:

[-2,-1)U(-1,4)

Answer 2

Write the set of points from -5 to 1 but excluding -4 and 1 as a union of intervals

Answer 3

(-5,1)U(-4,1)