Problem 85 - Precalculus Student Solutions Manual 5th

Question

Write each statement as an absolute value equation or inequality. \(p\) is within 0.0001 unit of 9.

Step-by-Step Solution

Answer

|p - 9| ≤ 0.0001

Step 1: Understand the Problem

We need to write an absolute value equation or inequality that describes the situation where a number, denoted as 𝑝, is within 0.0001 units of 9.

Step 2: Define the Range

Being within 0.0001 units of 9 means that the distance between 𝑝 and 9 is less than or equal to 0.0001. This can be written as the inequality: \[ |p - 9| \leq 0.0001 \]

Step 3: Write the Absolute Value Inequality

We now capture the condition mathematically. The problem requires an absolute value inequality, which we have already recognized as \[ |p - 9| \leq 0.0001 \]

Key Concepts

absolute value

Absolute value refers to the distance of a number from zero on the number line, no matter the direction. It’s always a positive number or zero. For example, the absolute value of both 5 and -5 is 5. The notation for absolute value uses vertical bars, like this: \(|5| = 5\) and \(|-5| = 5\).

In equations and inequalities, the absolute value symbol plays a crucial role, especially when expressing situations where the exact sign of the number may vary. It allows mathematicians to represent ranges and distances from a specific point or value.

For instance, in the given problem, \(|p - 9| \leq 0.0001\), it translates to the distance between \(p\) and 9 being less than or equal to 0.0001. The absolute value ensures that regardless of whether \(p\) is slightly above or below 9, this condition remains true.

inequalities

Inequalities are mathematical expressions that show how one quantity relates to another. They use symbols like \( > \), \( < \), \( \geq \), and \( \leq \) to denote relationships.

In an inequality such as \(|p - 9| \leq 0.0001\), the symbol \('\leq'\) means 'less than or equal to.' This indicates that the expression inside the absolute value is at most 0.0001 units away from 9.

Inequalities are vital in many real-world applications, including error margins in measurements and tolerances in manufacturing processes. They help in defining ranges and limits within which values can vary, ensuring precision and accuracy.

By using inequalities, we can effectively communicate the allowable deviation from a target value, ensuring desired outcomes.

distance

Distance, in mathematical terms, refers to how far apart two values are on the number line. It's a fundamental concept in absolute value problems.

The distance between two points \((x_1, x_2)\) can be found using the formula \[| x_1 - x_2 | \]. If we apply this to our example \(|p - 9| \leq 0.0001\), the distance between \(p\) and 9 must be at most 0.0001 units.

This concept is not restricted to just numbers; it applies to any measurement where an exact value is required but a tiny deviation is permissible.

Understanding distance in the context of absolute value allows students to solve problems more intuitively. By recognizing that the absolute value represents how far one number is from another, students can better grasp the meaning of inequalities and the importance of maintaining specific tolerances in various contexts.