inequalities

inequalities - tells us that a continuous function (graph...

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Section 3.8 - Steps in Solving Polynomial and Rational Inequalities STEP 1 : Write the inequality so that a polynomial or rational expression f is on the left side and zero is on the right side in one of the following forms: f(x) > 0 f(x) 0 f(x) < 0 f(x) 0 For rational expressions, be sure that the left side is written as a single quotient. This step converts the problem of solving an inequality into an equivalent (i.e., the same solution) problem of determining where a function is positive (or negative). STEP 2 : Factor f(x) to determine the numbers at which the expression f (x) on the left side equals zero and, if the expression is rational, the numbers at which the expression on the left side is undefined . We will call these numbers partition values. The Intermediate Value Theorem
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Unformatted text preview: tells us that a continuous function (graph can be drawn without raising the pencil from the paper) cannot change signs on an interval without having a zero in that interval. So the above partition values divide the x-axis into intervals on which the sign of f(x) CANNOT change. STEP 3 : Use the numbers found in STEP 2 to separate the real number line into intervals. We will construct a sign chart for the function f(x). STEP 4 : Determine the sign of f(x) on the intervals found in step 3. STEP 5 : The solution of the inequality includes all intervals with the correct sign (positive or negative). If the inequality is not strict , include the numbers at which f (x) is zero in the solution set. Be careful: The numbers which make f(x) undefined (i.e., the zeroes of the denominator in a rational function) are never included in the solution set....
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This note was uploaded on 12/11/2011 for the course MAC 1140 taught by Professor Kutter during the Fall '11 term at FSU.

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