Ch. 3 - Polynomial and Rational Functions

Lial13th EditionCollege AlgebraISBN: 9780136881063Not the one you use?Change textbook

Lial 13th Edition

Ch. 3 - Polynomial and Rational Functions

Problem 65

Chapter 4, Problem 65

Solve each rational inequality. Give the solution set in interval notation. 2 /(x - 2) ≥ 1 / x

Verified step by step guidance

Start by writing the inequality clearly: $\frac{2}{x - 2} \geq \frac{1}{x}$.

Bring all terms to one side to have a single rational expression: $\frac{2}{x - 2} - \frac{1}{x} \geq 0$.

Find a common denominator, which is $x(x - 2)$, and combine the fractions: $\frac{2x - (x - 2)}{x(x - 2)} \geq 0$.

Simplify the numerator: $2x - (x - 2) = 2x - x + 2 = x + 2$, so the inequality becomes $\frac{x + 2}{x(x - 2)} \geq 0$.

Determine the critical points by setting numerator and denominator equal to zero: $x + 2 = 0$, $x = 0$, and $x - 2 = 0$. These points divide the number line into intervals to test the sign of the expression and find where it is greater than or equal to zero.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Rational Inequalities

Rational inequalities involve expressions where variables appear in the denominator. Solving them requires finding values that satisfy the inequality while ensuring denominators are not zero, as division by zero is undefined.

Finding a Common Denominator and Combining Terms

To solve rational inequalities, rewrite both sides with a common denominator to combine terms into a single rational expression. This allows comparison to zero and simplifies the inequality into a form suitable for analysis.

Sign Analysis and Interval Notation

After simplifying, determine where the rational expression is positive, negative, or zero by analyzing critical points (zeros and undefined points). Use this to identify solution intervals and express the solution set clearly in interval notation.

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Interval Notation

Related Practice

Textbook Question

Show that the real zeros of each polynomial function satisfy the given conditions. See Example 6.

$ƒ (x) = x^{5} - 3 x^{3} + x + 2$ ; no real zero less than -3

Textbook Question

The remainder theorem indicates that when a polynomial ƒ(x) is divided by x-k, the remainder is equal to ƒ(k). Consider the polynomial function ƒ(x) = x³ - 2x² - x+2. Use the remainder theorem to find each of the following. Then determine the coordinates of the corresponding point on the graph of ƒ(x). ƒ (-2)

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Textbook Question

Graph each rational function. ƒ(x)=4/(x-1)

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Textbook Question

Solve each rational inequality. Give the solution set in interval notation. See Examples 4 and 5.

$\frac{5}{x + 3} \geq \frac{3}{x}$

Textbook Question

Find a polynomial function f of least degree having the graph shown. (Hint: See the NOTE following Example 4.)

Textbook Question

Graph each rational function. ƒ(x)=(6-3x)/(4-x)