Having problems with Df={x|-4<x<} = (4,-4]

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Having problems with Df={x|-4<x<} = (4,-4]

Postby chrisdacarnut » Thu Jun 04, 2009 1:14 pm

Df={x|-4<x<} = (4,-4]

I don't understand.

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Postby stapel_eliz » Thu Jun 04, 2009 8:15 pm

How does your book define "Df"?

The rest just looks like a typoed equivalence, showing the set-builder notation for an interval (assuming the second "less than" is supposed to be a "less than or equal to" sign) and the same interval in interval notation.

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Re: Having problems with this.

Postby jaybird0827 » Thu Jun 04, 2009 8:19 pm

chrisdacarnut wrote:Df={x|-4<x<} = (4,-4]

I don't understand.

The domain of function equals the set of all such that equals the half-open interval from to .

Actually, there are errors. Assuming that the interval part, is correct, the missing number (above) is , and the expression would better look like this:

Comment: should be less than or equal to because the interval is closed at the end. Since the same is open at the end, that would mean x is less than 4.

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