1. Fundamental Concepts
- Definition: The slope of a graph is a measure of its steepness, indicating the rate at which one variable changes with respect to another.
- Formula: The slope \(m\) of a line passing through two points \((x_1, y_1)\) and \((x_2, y_2)\) is given by \(m = \frac{{y_2 - y_1}}{{x_2 - x_1}}\).
- Interpretation: A positive slope indicates an upward trend, while a negative slope indicates a downward trend.
2. Key Concepts
Slope Calculation: $$m = \frac{{y_2 - y_1}}{{x_2 - x_1}}$$
Graphical Interpretation: The slope is the ratio of the vertical change (rise) to the horizontal change (run).
Application: Used in various fields such as physics, economics, and engineering to analyze trends and rates of change.
3. Examples
Example 1 (Basic)
Problem: Find the slope of the line passing through the points \((2, 3)\) and \((4, 7)\).
Step-by-Step Solution:
- Identify the coordinates: \((x_1, y_1) = (2, 3)\) and \((x_2, y_2) = (4, 7)\).
- Apply the slope formula: \(m = \frac{{7 - 3}}{{4 - 2}}\).
- Calculate the slope: \(m = \frac{{4}}{{2}} = 2\).
Validation: Substitute the points into the slope formula to ensure consistency.
Example 2 (Intermediate)
Problem: Determine the slope of the line represented by the equation \(2x - 3y + 6 = 0\).
Step-by-Step Solution:
- Rearrange the equation into slope-intercept form \(y = mx + b\): \(2x - 3y + 6 = 0 \Rightarrow -3y = -2x - 6 \Rightarrow y = \frac{2}{3}x + 2\).
- The coefficient of \(x\) gives the slope: \(m = \frac{2}{3}\).
Validation: Check that the rearranged equation matches the original.
4. Problem-Solving Techniques
- Visual Strategy: Plot the points on a coordinate plane to visualize the slope.
- Error-Proofing: Double-check calculations by substituting values back into the slope formula.
- Concept Reinforcement: Practice with different types of problems to reinforce understanding.