Math Problem Statement

Find a vector equation and parametric equations for the line. (Use the parameter t.)

the line through the point 

(8, −9, 4)

 and parallel to the vector 

1, 5, − 

2

3

r(t) =   x(t), y(t), z(t)

=       

Solution

To find the vector equation and the parametric equations of the line, let's break it down step by step.

Step 1: Vector Equation of the Line

The vector equation of a line is given by the formula:

r(t)=r0+tv\mathbf{r}(t) = \mathbf{r}_0 + t \mathbf{v}

Where:

  • r0\mathbf{r}_0 is the position vector of a point on the line (we are given the point (8,9,4)(8, -9, 4)).
  • v\mathbf{v} is the direction vector of the line (we are given the vector 1,5,2\langle 1, 5, -2 \rangle).
  • tt is a parameter.

So, the vector equation becomes:

r(t)=8,9,4+t1,5,2\mathbf{r}(t) = \langle 8, -9, 4 \rangle + t \langle 1, 5, -2 \rangle

Simplifying this expression:

r(t)=8+t,9+5t,42t\mathbf{r}(t) = \langle 8 + t, -9 + 5t, 4 - 2t \rangle

Thus, the vector equation is:

r(t)=8+t,9+5t,42t\mathbf{r}(t) = \langle 8 + t, -9 + 5t, 4 - 2t \rangle

Step 2: Parametric Equations of the Line

To get the parametric equations, we simply express each component of the vector equation in terms of tt. The parametric equations are:

x(t)=8+tx(t) = 8 + t y(t)=9+5ty(t) = -9 + 5t z(t)=42tz(t) = 4 - 2t

Final Answer

  • The vector equation is:

r(t)=8+t,9+5t,42t\mathbf{r}(t) = \langle 8 + t, -9 + 5t, 4 - 2t \rangle

  • The parametric equations are:

x(t)=8+t,y(t)=9+5t,z(t)=42tx(t) = 8 + t, \quad y(t) = -9 + 5t, \quad z(t) = 4 - 2t

Would you like a further breakdown of these steps, or is there anything else you'd like to discuss?

Here are a few related questions:

  1. How would the parametric equations change if the line were in 2D instead of 3D?
  2. What is the geometric interpretation of a vector equation of a line?
  3. How would you find the direction vector if only two points on the line are given?
  4. How do you convert a vector equation of a line into parametric form?
  5. What is the relationship between the direction vector and the slope of a line in 2D?

Tip: Always verify the direction vector by ensuring it points in the correct direction and check the point for consistency with the line.

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Math Problem Analysis

Mathematical Concepts

Vector Geometry
Parametric Equations
Vector Equations of a Line

Formulas

Vector equation of a line: r(t) = r_0 + t * v
Parametric equations: x(t) = x_0 + t * v_x, y(t) = y_0 + t * v_y, z(t) = z_0 + t * v_z

Theorems

Line in 3D space
Direction vector
Vector addition

Suitable Grade Level

Grades 11-12