Problem 2

Question

Exer. 1-6: Sketch the line through \(A\) and \(B\), and find its slope \(m\). $$ A(4,-1), \quad B(-6,-3) $$

Step-by-Step Solution

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Answer
The slope of the line through points \( A(4,-1) \) and \( B(-6,-3) \) is \( \frac{1}{5} \).
1Step 1: Identify the coordinates of the points
We begin by identifying the coordinates of the given points. The coordinates of point \( A \) are \( (4, -1) \) and the coordinates of point \( B \) are \( (-6, -3) \).
2Step 2: Use the slope formula
The slope \( m \) of a line passing through two points \( (x_1, y_1) \) and \( (x_2, y_2) \) can be found using the formula: \[ m = \frac{y_2 - y_1}{x_2 - x_1} \] Plugging in the coordinates of points \( A \) and \( B \) into this formula gives: \[ m = \frac{-3 - (-1)}{-6 - 4} \]
3Step 3: Calculate the slope
Simplify the expression obtained in Step 2: \[ m = \frac{-3 + 1}{-6 - 4} = \frac{-2}{-10} = \frac{1}{5} \] Thus, the slope of the line connecting points \( A \) and \( B \) is \( \frac{1}{5} \).
4Step 4: Sketch the line
To sketch the line, plot points \( A(4, -1) \) and \( B(-6, -3) \) on a coordinate plane. After plotting, draw a straight line passing through both points. This line represents the line determined by points \( A \) and \( B \) with a slope of \( \frac{1}{5} \).

Key Concepts

Coordinate GeometryPlotting PointsLinear Equations
Coordinate Geometry
Coordinate geometry, also known as analytic geometry, is the study of geometry using a coordinate system. The coordinate plane is a two-dimensional surface formed by two axes: the x-axis (horizontal) and the y-axis (vertical).
These axes intersect at a point called the origin, with coordinates (0, 0).
In this exercise, the points A and B have specific coordinates: A(4, -1) and B(-6, -3). These are plotted using ordered pairs where the first value indicates the position on the x-axis, and the second indicates the position on the y-axis. This method allows for precise placement of points on the plane and is critical in forming lines, curves, and other geometric figures.
  • Understanding the coordinate axes: The x-axis is horizontal, and the y-axis is vertical.
  • Coordinates: Each point on the plane is represented by an ordered pair (x, y).
Coordinate geometry is not only used in mathematics but also plays a crucial role in fields such as engineering, physics, and computer graphics.
Plotting Points
Plotting points on a coordinate grid is a foundational skill in coordinate geometry. It involves locating a point using its coordinates.
In our example, point A is at (4, -1) and point B is at (-6, -3). This means for point A, move 4 units along the x-axis and then 1 unit down the y-axis. For point B, move 6 units left along the x-axis and 3 units down the y-axis.
Once the points are plotted, you can draw a line to visualize the connection between them. This concept is powerful, as it allows you to visualize mathematical problems effectively.
  • Use a ruler for precision when sketching lines.
  • Ensure the scale used on the axes is consistent to maintain accuracy.
  • Check your plotted points by verifying their coordinates on the axes.
Plotting these points accurately sets the stage for further exploration of lines and their properties, such as slope.
Linear Equations
The concept of linear equations comes into play when understanding the lines formed by plotting points. A linear equation is an algebraic equation in which each term is either a constant or the product of a constant and a single variable.
When we talk about the line through points A and B with a slope of \( \frac{1}{5} \), we can represent it with a linear equation. The general form of a linear equation is \( y = mx + c \), where \( m \) is the slope and \( c \) is the y-intercept. In our case, with a slope of \( \frac{1}{5} \), the equation can define the behavior of the line between points A and B.
Understanding the slope, \( m \), of a line is crucial. Here, it represents the change in y for a unit change in x. In simpler terms, for every step to the right along the line, the height of the line increases by a fraction defined by the slope.
  • Slope: Determines the steepness of the line.
  • General Equation Form: \( y = mx + c \) is key in determining a line's formula.
This formula helps in forming linear equations which can be solved to find intersections, determine parallel lines, or even evaluate the consistency of plotted data.