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Equation of a plane

Problem 9.133 · hard

Find an equation of the plane through the points \( \displaystyle (1, -2, -3),\ (-3, -2, 3),\ (2, 2, 1) \).

\[ \left[\begin{matrix}-4\\0\\6\end{matrix}\right] \]
PQ.✓ Proved
\[ \left[\begin{matrix}1\\4\\4\end{matrix}\right] \]
PR.✓ Proved
\[ \left[\begin{matrix}-12\\11\\-8\end{matrix}\right] \]
A normal vector n = PQ × PR (scaled).✓ Proved
\[ -10 \]
n · P gives the constant.✓ Proved
The plane is -12*x + 11*y - 8*z = -10.
Reviewed

Answer \( - 12 x + 11 y - 8 z = -10 \)

✓ Nihil obstat Lines: 4 proved, 1 reviewed. The answer was also checked a second way, without looking at the solution. Reviewers found nothing wrong with the explanation.

The full receipt

Line	Status	Checked by	Detail
1	✓ Proved	sympy 1.14.0	simplify(lhs - rhs) reduced to 0
2	✓ Proved	sympy 1.14.0	simplify(lhs - rhs) reduced to 0
3	✓ Proved	sympy 1.14.0	simplify(lhs - rhs) reduced to 0
4	✓ Proved	sympy 1.14.0	simplify(lhs - rhs) reduced to 0
5	Reviewed	reviewers: gpt-oss:20b, qwen3.6:27b-mlx	a sentence; read, not computed
answer, a second way	✓ Checked independently	sympy 1.14.0 + mpmath 1.3.0	all three points satisfy the equation

Reviewers

gpt-oss:20b: pass
qwen3.6:27b-mlx: pass — The solution correctly computes the direction vectors, their cross product to find the normal vector, and the constant term using the point-normal form. The final equation matches the stated answer.

Every verdict on record (4)

qwen3.6:27b-mlx: pass 2026-09-27 — The solution correctly computes the direction vectors, their cross product to find the normal vector, and the constant term using the point-normal form. The final equation matches the stated answer.
gpt-oss:20b: pass 2026-09-27
qwen3.6:27b-mlx: pass 2026-09-27 — The solution correctly identifies the vectors, computes the normal vector via cross product, and determines the constant term to form the plane equation. The final equation matches the stated answer.
gpt-oss:20b: pass 2026-09-27

Proved: SymPy reduced the difference between the two sides to zero. Checked independently: a separate method, named above, confirmed it. Checked numerically: the two sides agree at every sampled point, which is evidence, not proof. Reviewed: a model or a person read it; that is all a sentence can have. Solution by generator:structured/plane_through_points, checked 2026-09-27 with SymPy 1.14.0.