Math Problem Statement

Find an equation in x, y, z for the plane that passes through the points: P(1, -1, 3), Q(2, -1, 2), R(3, 0, 3).

Solution

To solve the problem in the image, we need to determine the equation of the plane that passes through the given points P(1,1,3)P(1, -1, 3), Q(2,1,2)Q(2, -1, 2), and R(3,0,3)R(3, 0, 3).

Step 1: Find the vectors

We need two vectors that lie on the plane. These can be obtained from the given points:

  • Vector PQ=QP=(21,1(1),23)=(1,0,1)\mathbf{PQ} = Q - P = (2 - 1, -1 - (-1), 2 - 3) = (1, 0, -1)
  • Vector PR=RP=(31,0(1),33)=(2,1,0)\mathbf{PR} = R - P = (3 - 1, 0 - (-1), 3 - 3) = (2, 1, 0)

Step 2: Find the normal vector

The normal vector to the plane can be found by taking the cross product of PQ\mathbf{PQ} and PR\mathbf{PR}.

n=PQ×PR=ijk101210\mathbf{n} = \mathbf{PQ} \times \mathbf{PR} = \begin{vmatrix} \mathbf{i} & \mathbf{j} & \mathbf{k} \\ 1 & 0 & -1 \\ 2 & 1 & 0 \end{vmatrix}

n=i(0(0)(1)(1))j(1(0)(1)(2))+k(1(1)0(2))\mathbf{n} = \mathbf{i} \left( 0(0) - (-1)(1) \right) - \mathbf{j} \left( 1(0) - (-1)(2) \right) + \mathbf{k} \left( 1(1) - 0(2) \right)

n=i(1)j(2)+k(1)\mathbf{n} = \mathbf{i}(1) - \mathbf{j}(2) + \mathbf{k}(1)

So the normal vector is n=(1,2,1)\mathbf{n} = (1, -2, 1).

Step 3: Use the normal vector to find the plane equation

The general form of the plane equation is: a(xx1)+b(yy1)+c(zz1)=0a(x - x_1) + b(y - y_1) + c(z - z_1) = 0 where (x1,y1,z1)(x_1, y_1, z_1) is a point on the plane (e.g., point P(1,1,3)P(1, -1, 3)) and n=(a,b,c)=(1,2,1)\mathbf{n} = (a, b, c) = (1, -2, 1).

Substitute the values: 1(x1)2(y+1)+1(z3)=01(x - 1) - 2(y + 1) + 1(z - 3) = 0 Simplifying: x12y2+z3=0x - 1 - 2y - 2 + z - 3 = 0 x2y+z6=0x - 2y + z - 6 = 0

Step 4: Conclusion

The equation of the plane is x2y+z=6x - 2y + z = 6, which corresponds to the second option in the provided choices: x2y+z6=0x - 2y + z - 6 = 0

Would you like further details or have any questions?

Related Questions:

  1. How do you calculate the cross product of two vectors?
  2. What is the geometric meaning of the normal vector to a plane?
  3. How do you find the equation of a plane using three points in space?
  4. How do you verify if a point lies on a plane?
  5. What is the significance of the coefficients in the equation of a plane?

Tip:

When solving plane equations, always check the normal vector, as it determines the orientation of the plane in space.

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Math Problem Analysis

Mathematical Concepts

Linear Algebra
Vectors
Planes
Cross Product

Formulas

Vector subtraction: \( \mathbf{AB} = B - A \)
Cross product: \( \mathbf{a} \times \mathbf{b} \)
Equation of a plane: \( a(x - x_1) + b(y - y_1) + c(z - z_1) = 0 \)

Theorems

Cross Product to find normal vector
Equation of a Plane using a Point and a Normal Vector

Suitable Grade Level

Grades 11-12