Math Problem Statement

get all coordinates of P on x axis so that line that cross A(1,2) and P are perpendicular to line that cross B(8,3) and P

Solution

To find all coordinates P(x,0)P(x, 0) on the xx-axis such that the line passing through A(1,2)A(1, 2) and PP is perpendicular to the line passing through B(8,3)B(8, 3) and PP, we need to use the condition for perpendicular lines.

Step-by-Step Solution:

  1. Equation for the slopes: The condition for perpendicular lines is that the product of their slopes must be 1-1. If the slope of the line passing through points AA and PP is m1m_1, and the slope of the line passing through points BB and PP is m2m_2, we have: m1m2=1m_1 \cdot m_2 = -1

  2. Slope of line APAP: The slope m1m_1 of the line through A(1,2)A(1, 2) and P(x,0)P(x, 0) is: m1=02x1=2x1m_1 = \frac{0 - 2}{x - 1} = \frac{-2}{x - 1}

  3. Slope of line BPBP: The slope m2m_2 of the line through B(8,3)B(8, 3) and P(x,0)P(x, 0) is: m2=03x8=3x8m_2 = \frac{0 - 3}{x - 8} = \frac{-3}{x - 8}

  4. Perpendicularity condition: Using the condition m1m2=1m_1 \cdot m_2 = -1, we substitute the slopes: (2x1)(3x8)=1\left( \frac{-2}{x - 1} \right) \cdot \left( \frac{-3}{x - 8} \right) = -1 Simplifying this: 6(x1)(x8)=1\frac{6}{(x - 1)(x - 8)} = -1

  5. Solve the equation: Multiply both sides by (x1)(x8)(x - 1)(x - 8): 6=(x1)(x8)6 = -(x - 1)(x - 8) Expand the right-hand side: 6=(x29x+8)6 = -(x^2 - 9x + 8) Simplifying: 6=x2+9x86 = -x^2 + 9x - 8 Bring everything to one side: x29x+14=0x^2 - 9x + 14 = 0

  6. Solve the quadratic equation: We can solve the quadratic equation x29x+14=0x^2 - 9x + 14 = 0 using the quadratic formula: x=(9)±(9)24(1)(14)2(1)x = \frac{-(-9) \pm \sqrt{(-9)^2 - 4(1)(14)}}{2(1)} Simplifying: x=9±81562=9±252x = \frac{9 \pm \sqrt{81 - 56}}{2} = \frac{9 \pm \sqrt{25}}{2} x=9±52x = \frac{9 \pm 5}{2} So, we have two solutions: x=9+52=7orx=952=2x = \frac{9 + 5}{2} = 7 \quad \text{or} \quad x = \frac{9 - 5}{2} = 2

Conclusion:

The two possible coordinates for PP on the xx-axis are P(7,0)P(7, 0) and P(2,0)P(2, 0).


Do you want more details on any step or have any questions?

Here are 5 related questions to consider:

  1. How would the solution change if PP were not constrained to the xx-axis?
  2. What is the geometric interpretation of the perpendicularity condition?
  3. How can the condition for perpendicularity be generalized for three-dimensional space?
  4. How can the equation of a perpendicular bisector be derived from two points?
  5. How do you solve the quadratic equation geometrically?

Tip: Always check the geometry of a problem involving slopes to ensure the condition, such as perpendicularity, holds geometrically.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Coordinate Geometry
Slopes of Lines
Perpendicularity Condition
Quadratic Equations

Formulas

Slope formula: m = (y2 - y1) / (x2 - x1)
Perpendicularity condition: m1 * m2 = -1
Quadratic equation: ax^2 + bx + c = 0
Quadratic formula: x = (-b ± √(b^2 - 4ac)) / 2a

Theorems

Condition for Perpendicular Slopes
Quadratic Formula

Suitable Grade Level

Grades 9-12