Parametric Eqs: Find Line & Plane, Find Triangle Area

In summary: I now expect him to come back with another thread asking what the symbol $\times$ means.In summary, the conversation discusses deriving parametric equations for a line and the equation of a plane without using known formulas, as well as finding the area of a triangle with given vertices. The OP has not shown any attempt at solving the problems himself and has posted the same questions on multiple math help sites.
  • #1
brinlin
13
0
Let P (1, 2, 3), Q (2, 3, 1), and R (3, 1, 2).
(a) Derive the parametric equations for the line that passes through P and Q without resorting
to the known formula.
(b) Derive the equation of the plane that passes through the points P, Q, and R without
resorting to the known formula.
(c) Find the area of the triangle with vertices P, Q, and R.
 
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  • #3
skeeter said:
(a) initial point + (direction vector) times t

(b) Calculus III - Equations of Planes (lamar.edu)

(c) area = $\dfrac{1}{2} |\vec{PQ} \times \vec{PR} |$

And I would hope that the OP would have found $\displaystyle \vec{PQ} \times \vec{PR}$ in part b) :P
 
  • #4
Prove It said:
And I would hope that the OP would have found $\displaystyle \vec{PQ} \times \vec{PR}$ in part b) :p

seeing how the OP has posted the same problems on two other math help sites, I would hope so, also
 
Last edited by a moderator:
  • #5
It is not clear to me whether the OP's problem is with math or with reading English. He does not appear to have read, or understood, the instructions for this board. He has posted 8 or more threads without showing any attempt to solve them himself. I feel that I, at least, have already done too much.
 

FAQ: Parametric Eqs: Find Line & Plane, Find Triangle Area

What are parametric equations?

Parametric equations are a set of equations that express a set of variables as functions of one or more independent variables, typically represented by the letters t or s. These equations are commonly used to describe curves, lines, and surfaces in mathematics and physics.

How do I find the equation of a line using parametric equations?

To find the equation of a line using parametric equations, you will need to have two points on the line and a parameter (usually t). Use the formula x = x1 + at and y = y1 + bt, where (x1, y1) are the coordinates of one point and a and b are the differences between the x and y coordinates of the two points. This will give you the parametric equations for the line, which you can then rearrange to get the equation in slope-intercept form if desired.

How do I find the equation of a plane using parametric equations?

To find the equation of a plane using parametric equations, you will need to have three points on the plane and two parameters (usually s and t). Use the formula x = x1 + as + bt, y = y1 + cs + dt, and z = z1 + es + ft, where (x1, y1, z1) are the coordinates of one point and a, b, c, d, e, and f are the differences between the coordinates of the other two points. This will give you the parametric equations for the plane, which you can then rearrange to get the equation in standard form if desired.

How do I find the area of a triangle using parametric equations?

To find the area of a triangle using parametric equations, you will need to have the coordinates of the three vertices of the triangle. Use the formula A = 1/2 * |(x1y2 + x2y3 + x3y1 - x1y3 - x2y1 - x3y2)|, where (x1, y1), (x2, y2), and (x3, y3) are the coordinates of the vertices. This will give you the area of the triangle in square units.

How are parametric equations used in real life?

Parametric equations are used in a variety of real-life applications, including physics, engineering, and computer graphics. They are commonly used to describe the motion of objects, such as projectiles or vehicles, and to model natural phenomena, such as the movement of waves or the growth of populations. They are also used in computer graphics to create realistic animations and simulations.

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