Planes in 3D Math Example 1

Follow the full solution, then compare it with the other examples linked below.

Example 1

easy
Write the equation of the plane with normal vector โŸจ2,โˆ’3,1โŸฉ\langle 2, -3, 1 \rangle passing through the point (1,4,โˆ’2)(1, 4, -2).

Solution

  1. 1
    The equation of a plane with normal โŸจA,B,CโŸฉ\langle A, B, C \rangle through (x0,y0,z0)(x_0, y_0, z_0) is A(xโˆ’x0)+B(yโˆ’y0)+C(zโˆ’z0)=0A(x-x_0) + B(y-y_0) + C(z-z_0) = 0.
  2. 2
    Substitute: 2(xโˆ’1)โˆ’3(yโˆ’4)+1(z+2)=02(x-1) - 3(y-4) + 1(z+2) = 0.
  3. 3
    Expand: 2xโˆ’2โˆ’3y+12+z+2=02x - 2 - 3y + 12 + z + 2 = 0, so 2xโˆ’3y+z+12=02x - 3y + z + 12 = 0.

Answer

2xโˆ’3y+z+12=02x - 3y + z + 12 = 0
A plane in 3D is determined by a point on the plane and a normal vector perpendicular to it. The normal vector's components become the coefficients of xx, yy, and zz in the plane's equation. This generalizes the concept of a line (in 2D) having a perpendicular direction.

About Planes in 3D

A flat, infinite surface in 3D space described by ax+by+cz=dax + by + cz = d, where โŸจa,b,cโŸฉ\langle a, b, c \rangle is the normal vector.

Learn more about Planes in 3D โ†’

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