Home›Calculus 3›Equation of a plane›Problem 9.109

Equation of a plane

Problem 9.109 · hard

Find an equation of the plane through the points \( \displaystyle (-3, 2, 1),\ (3, -2, 0),\ (-3, 3, 3) \).

\[ \left[\begin{matrix}6\\-4\\-1\end{matrix}\right] \]
PQ.✓ Proved
\[ \left[\begin{matrix}0\\1\\2\end{matrix}\right] \]
PR.✓ Proved
\[ \left[\begin{matrix}-7\\-12\\6\end{matrix}\right] \]
A normal vector n = PQ × PR (scaled).✓ Proved
\[ 3 \]
n · P gives the constant.✓ Proved
The plane is -7*x - 12*y + 6*z = 3.
Reviewed

Answer \( - 7 x - 12 y + 6 z = 3 \)

✓ 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 normal vector via cross product and determines the constant term. The final equation matches the stated answer.

Every verdict on record (4)

qwen3.6:27b-mlx: pass 2026-09-26 — The solution correctly computes the normal vector via cross product and determines the constant term. The final equation matches the stated answer.
gpt-oss:20b: pass 2026-09-26
qwen3.6:27b-mlx: pass 2026-09-26 — The solution correctly computes the normal vector via the cross product of displacement vectors and determines the constant term using a point on the plane. The final equation is correct.
gpt-oss:20b: pass 2026-09-26

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 2026-09-26 with SymPy 1.14.0.