Someone asked… Whenever you have a problem with an inequality that has an equal sign on it, what part of the intervals have brackets on them??
Good question.
If the inequality is a polynomial, like the top half of the assignment from Chapter 3 Section 6, then you use brackets on all the intervals. But not on the infinity ends, of course.
If the inequality involves rational functions, like the bottom half of the assignment, then you use brackets on the zeros from the numerator. The zeros from the denominator must be avoid — dangerous, these are domain concerns, they cannot be included in the final solution, so they get parenthesis. Zeros from the numerator get brackets.
