Math Problem Statement

a line contains the points (-2,8) and (-5,-8), each corresponding to a value of the parameter t. if the point (-2,8) corresponded with with the parameter value t = 2, and the point (-5,-8) corresponded with the parameter value t = 0, what would the parametric equations of the line be

Solution

We are given two points (2,8)(-2, 8) and (5,8)(-5, -8) that lie on a line, with the corresponding parameter values t=2t = 2 and t=0t = 0, respectively. We need to find the parametric equations of the line.

Step 1: General form of parametric equations

The parametric equations of a line are typically expressed as: x=x0+atx = x_0 + at y=y0+bty = y_0 + bt where (x0,y0)(x_0, y_0) is a point on the line, and aa and bb represent the direction ratios (change in xx and yy per unit change in tt).

Step 2: Find the direction ratios aa and bb

To find the direction ratios, we can calculate the change in xx and yy between the two given points.

For the xx-coordinate: Δx=x1x2=2(5)=3\Delta x = x_1 - x_2 = -2 - (-5) = 3 For the yy-coordinate: Δy=y1y2=8(8)=16\Delta y = y_1 - y_2 = 8 - (-8) = 16

Since the change in tt between these two points is 20=22 - 0 = 2, the direction ratios aa and bb will be: a=ΔxΔt=32,b=ΔyΔt=162=8a = \frac{\Delta x}{\Delta t} = \frac{3}{2}, \quad b = \frac{\Delta y}{\Delta t} = \frac{16}{2} = 8

Step 3: Write the parametric equations

Now, we can use the point (5,8)(-5, -8) at t=0t = 0 as the initial point (x0,y0)(x_0, y_0), and the direction ratios a=32,b=8a = \frac{3}{2}, b = 8.

The parametric equations of the line will be: x(t)=5+32tx(t) = -5 + \frac{3}{2}t y(t)=8+8ty(t) = -8 + 8t

Thus, the parametric equations of the line are: x(t)=5+32t,y(t)=8+8tx(t) = -5 + \frac{3}{2}t, \quad y(t) = -8 + 8t

Would you like more details on any part of the process? Here are some related questions:

  1. How do we convert parametric equations to a Cartesian form?
  2. What are the direction ratios, and how do they relate to the slope of the line?
  3. Can you explain how to graph parametric equations step by step?
  4. What happens if the parameter tt corresponds to different values for other points?
  5. How can we derive parametric equations for curves other than lines?

Tip:

When dealing with parametric equations, it's often helpful to find the direction ratios, as they determine how fast each variable changes with respect to the parameter.

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Math Problem Analysis

Mathematical Concepts

Parametric Equations
Linear Algebra
Coordinate Geometry

Formulas

x(t) = x_0 + at
y(t) = y_0 + bt
a = (x_1 - x_2) / Δt
b = (y_1 - y_2) / Δt

Theorems

Parametric representation of lines

Suitable Grade Level

Grades 9-11