How could be an answer to this problem? We are looking for a number, not an interval. You may have looked at the wrong key. If not, the answer in the key is wrong.
In the book I am working from I was asked to solve the following:
This is how I worked it out:
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Question, did I worked this problem wrong?! as I finished working it out I checked with the book's answer and I was given this as an answer {-1, 1}.
Could that book have a missprint or is it me?
Much thanks in advance!!!