Perpendicular Lines and Equations of Straight Lines
This page delves into the properties of perpendicular lines and the methods for finding equations of straight lines.
Key concepts covered include:
- Gradients of perpendicular lines
- General equation of a straight line
- Point-slope form of a line equation
Vocabulary: Perpendicular lines are lines that intersect at right angles 90degrees.
Formula: The equation of a straight line formula is y = mx + c, where m is the gradient and c is the y-intercept.
Highlight: For perpendicular lines, the product of their gradients is always -1.
Example: Given points A4,7 and B3,−10, the gradient of line AB is calculated as m = 7−(−10)/4−3 = 17.
The page also demonstrates how to find the equation of a line using the point-slope form: y - y₁ = mx−x1, where x1,y1 is a point on the line and m is the gradient.
Example: For line CD with gradient -1/3 passing through point D1,5, the equation is derived as: y - 5 = -1/3x−1, which simplifies to x + 3y - 16 = 0.