# Help Exam in one hour Find equation of plane?

• cjavier
In summary, to find the equation of a plane containing two given lines, we first find the direction vectors of both lines. Then, we take the cross product of the direction vectors to find the normal vector of the plane. Using this normal vector and a point on either of the two lines, we can find the equation of the plane.
cjavier
Find an equation of the plane containing the two lines?
The lines are:

(x - 2) / -3 = (y + 1) / 2 = (z - 3) / 1 and (x - 8) / -1 = (y + 5) / -2 = (z -1) / 4

cjavier said:
Find an equation of the plane containing the two lines?
The lines are:

(x - 2) / -3 = (y + 1) / 2 = (z - 3) / 1 and (x - 8) / -1 = (y + 5) / -2 = (z -1) / 4

Can you find the direction vector of both lines? What does the cross product of two vectors give us with respect to information about the plane?

chiro said:
Can you find the direction vector of both lines? What does the cross product of two vectors give us with respect to information about the plane?

Before I dive in can I clarify, the direction vector of line one is <-3, 2, 1> and line 2 is <-1, -2, 4> and by taking the cross product I find the normal vector of the plane. With this normal vector, I can take a point, either (2, -1, 3) OR (8, -5, 1) and use the normal vector to find the equation of the plane?

## 1. What is the equation of a plane?

The equation of a plane is typically written in the form Ax + By + Cz + D = 0, where A, B, and C are the coefficients of the variables x, y, and z, and D is a constant term. This equation represents all the points that lie on the plane in a three-dimensional coordinate system.

## 2. How do I find the equation of a plane given three points?

To find the equation of a plane given three points, you can use the point-normal form of the equation. First, find the normal vector of the plane by calculating the cross product of two vectors that lie on the plane. Then, plug in one of the given points and the normal vector into the point-normal form equation to find the equation of the plane.

## 3. Can I find the equation of a plane if I only have two points?

No, you need at least three points to uniquely determine the equation of a plane. With two points, there are infinitely many planes that can contain those points.

## 4. What is the significance of the coefficients in the equation of a plane?

The coefficients A, B, and C represent the direction of the plane's normal vector. The normal vector is perpendicular to the plane and is used to define the orientation of the plane in space. The constant term D determines the distance of the plane from the origin.

## 5. How can I use the equation of a plane to solve problems?

The equation of a plane can be used to solve various problems in geometry and physics, such as finding the distance between a point and a plane, determining if a line is parallel to a plane, or calculating the angle between two intersecting planes. It can also be used in applications like 3D modeling and computer graphics.

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