Math Problem Statement

Tentukan peta garis y + 2x - 4 = 0 jika dirotasi pada titik O(0, 0) sejauh -90°

Solution

The problem is asking to find the image of the line y+2x4=0y + 2x - 4 = 0 when rotated by 90-90^\circ around the origin (0,0)(0, 0).

Steps to solve:

  1. Rewrite the line equation in slope-intercept form: y=2x+4y = -2x + 4 This has a slope of 2-2 and a y-intercept of 4.

  2. Understand rotation of points: When a point (x,y)(x, y) is rotated counterclockwise by 90-90^\circ (which is clockwise), the transformation is given by: (x,y)=(y,x)(x', y') = (y, -x)

  3. Transform the line under rotation: To rotate the entire line, substitute each point (x,y)(x, y) on the line and apply the transformation.

    Since the original equation is y=2x+4y = -2x + 4, substitute into the rotation formula:

    • The original line: y=2x+4y = -2x + 4
    • Rotation by 90-90^\circ: Each point on the line (x,y)(x, y) transforms to (y,x)(y, -x).
  4. Apply the transformation:

    • The new xx' will be the old yy, and the new yy' will be the negative of the old xx.

    This leads to the transformed equation: x=2y+4x' = -2y' + 4 Rearranging for standard linear form, the equation becomes: x+2y4=0x' + 2y' - 4 = 0

Thus, after a 90-90^\circ rotation around the origin, the image of the line is: x+2y4=0x + 2y - 4 = 0

Would you like any further clarifications or details on this solution?

Here are 5 related questions to expand on the topic:

  1. How do rotations affect the slopes of lines in general?
  2. What is the transformation matrix for a +90+90^\circ rotation around the origin?
  3. How would the line change if rotated by 180180^\circ instead?
  4. Can the rotation of more complex curves (e.g., circles or parabolas) be handled similarly?
  5. How does translation affect a line differently compared to rotation?

Tip: Understanding transformations geometrically can make it easier to visualize how shapes and lines behave under rotation or translation.

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Math Problem Analysis

Mathematical Concepts

Coordinate Geometry
Line Rotation
Linear Equations

Formulas

(x', y') = (y, -x) for a -90° rotation
Standard linear equation form: ax + by + c = 0

Theorems

Line Rotation Theorem
Coordinate Transformation

Suitable Grade Level

Grades 10-12