Math Problem Statement

A line y=2x−3y=2x−3 is reflected across the line y=x+4y=x+4. Determine the equation of the reflection of the line.

What is required?

Find the reflection of the line across another line.

Solution

To reflect the line y=2x3y = 2x - 3 across another line y=x+4y = x + 4, we need to go through a series of steps. Here is a detailed step-by-step solution for this transformation:

Steps for Reflection Across a Line

  1. Step 1: Parameterize the first line equation y=2x3y = 2x - 3.

    • This is the original line that we want to reflect.
    • In parametric form, each point P(x,y)P(x, y) on the line satisfies the equation y=2x3y = 2x - 3.
  2. Step 2: Find the general formula for reflecting a point.

    • To reflect a point P(x1,y1)P(x_1, y_1) across a line y=mx+by = mx + b (in this case, y=x+4y = x + 4), we can use the following procedure:
      • We find the perpendicular distance between the point and the reflection line.
      • Then, we calculate the reflected point by applying reflection formulas.
  3. Step 3: Use the formula for reflecting a line across y=x+4y = x + 4.

    • To reflect across the line y=x+4y = x + 4, we first translate the line by subtracting 4 from all yy-coordinates. The reflection across y=xy = x (the diagonal) involves swapping xx and yy. Finally, we translate back by adding 4 to the yy-coordinates.
  4. Step 4: Apply reflection formulas for lines. The reflection of a line across another line involves finding the new slope and intercept for the reflected line. When reflecting over y=xy = x, the equation of the line transforms as follows: y=mx+bbecomesx=my+by = mx + b \quad \text{becomes} \quad x = my + b' After solving for yy, we get the new line equation. This process needs to account for translations if the reflection line is not simply y=xy = x.

  5. Step 5: Calculate the reflection. Let's reflect the given line y=2x3y = 2x - 3 across the line y=x+4y = x + 4.


Let me calculate the exact equation of the reflected line using the necessary transformations for reflection across y=x+4y = x + 4.

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Math Problem Analysis

Mathematical Concepts

Coordinate Geometry
Line Reflections
Linear Equations

Formulas

Reflection of a point across a line formula
Slope-intercept form of a line: y = mx + b

Theorems

Reflection of a point or line across another line
Transformation properties in coordinate geometry

Suitable Grade Level

Grades 10-12