Math Problem Statement

Find the vector and Cartesian equations of the line passing through the points (-2, 0, 3) and (3, 5, -2).

Solution

To solve the problem, we will determine both the vector equation and the Cartesian equation of the line passing through the points (2,0,3)(-2, 0, 3) and (3,5,2)(3, 5, -2).


1. Vector Equation of the Line

The general form of the vector equation of a line is:

r=a+tb\mathbf{r} = \mathbf{a} + t \mathbf{b}

Where:

  • a\mathbf{a} is a position vector of a point on the line (we can use (2,0,3)(-2, 0, 3)),
  • b\mathbf{b} is the direction vector of the line, which is determined by the difference between the two points, i.e., b=(3(2),50,23)\mathbf{b} = (3 - (-2), 5 - 0, -2 - 3).

Calculate b\mathbf{b}:

b=(5,5,5)\mathbf{b} = (5, 5, -5)

Thus, the vector equation of the line is: r=(2,0,3)+t(5,5,5),tR\mathbf{r} = (-2, 0, 3) + t (5, 5, -5), \quad t \in \mathbb{R}

In expanded form: r=(2+5t,5t,35t)\mathbf{r} = (-2 + 5t, 5t, 3 - 5t)


2. Cartesian Equation of the Line

To find the Cartesian equation, we eliminate the parameter tt from the vector equation. From the parametric equations: x=2+5t,y=5t,z=35tx = -2 + 5t, \quad y = 5t, \quad z = 3 - 5t

Solving for tt in terms of x,y,zx, y, z:

  • From x=2+5tx = -2 + 5t: t=x+25t = \frac{x + 2}{5},
  • From y=5ty = 5t: t=y5t = \frac{y}{5},
  • From z=35tz = 3 - 5t: t=3z5t = \frac{3 - z}{5}.

Equating these expressions for tt: x+25=y5=3z5\frac{x + 2}{5} = \frac{y}{5} = \frac{3 - z}{5}

Remove the denominator to simplify: x+2=y=3zx + 2 = y = 3 - z

Rearrange to write the Cartesian equations: x+2=y,y+z=3x + 2 = y, \quad y + z = 3


Final Answer:

  1. Vector Equation: r=(2,0,3)+t(5,5,5),tR\mathbf{r} = (-2, 0, 3) + t (5, 5, -5), \quad t \in \mathbb{R}

  2. Cartesian Equations: x+2=y,y+z=3x + 2 = y, \quad y + z = 3


Would you like further details or explanations on any part of the solution? Here are some related questions:

  1. How is the direction vector calculated from two points?
  2. What does the parameter tt represent in the vector equation?
  3. How can we verify that the Cartesian and vector equations describe the same line?
  4. What are some real-world applications of these equations in 3D geometry?
  5. How do you convert between vector and Cartesian forms systematically?

Tip: Always cross-check your direction vector to ensure it is accurate, as it forms the backbone of all line equations.

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Math Problem Analysis

Mathematical Concepts

Vector Equations
Cartesian Equations
3D Geometry

Formulas

Vector equation of a line: r = a + t * b
Cartesian equation of a line derived from parametric equations

Theorems

Concept of direction vectors in 3D space

Suitable Grade Level

Grades 10-12