Converting between polar and rectangular coordinates
Problem 8.176 · easy
Convert the polar point \( \displaystyle \left(2, \frac{3 \pi}{4}\right) \) to rectangular coordinates.
- \[ \left[\begin{matrix}- \sqrt{2}\\\sqrt{2}\end{matrix}\right] \]x = r cos θ, y = r sin θ.✓ Proved
Answer \( \left(- \sqrt{2}, \sqrt{2}\right) \)
✓ Nihil obstat Every line of this solution was proved by the computer algebra system SymPy. 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 |
| answer, a second way | ✓ Checked independently | sympy 1.14.0 + mpmath 1.3.0 | floating point |
Reviewers
gpt-oss:20b: passqwen3.6:27b-mlx: pass — The solution correctly applies the polar to rectangular conversion formulas and arrives at the correct coordinates.
Every verdict on record (4)
qwen3.6:27b-mlx: pass 2026-10-08 — The solution correctly applies the polar to rectangular conversion formulas and arrives at the correct coordinates.gpt-oss:20b: pass 2026-10-08gpt-oss:20b: pass 2026-10-08qwen3.6:27b-mlx: fail (style) 2026-10-08 — The solution lacks the intermediate calculation steps showing how r and theta are substituted into the conversion formulas. It jumps directly to the final matrix equality without demonstrating the work.
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/polar_conversion, checked 2026-10-08 with SymPy 1.14.0.