Derivative of \( \displaystyle \frac{10 x + 3}{5 x - 4} \)
Problem 2.328 · medium
Differentiate \( \displaystyle f(x) = \frac{10 x + 3}{5 x - 4} \).
- \[ \frac{d}{d x} \frac{10 x + 3}{5 x - 4} \]derivative rewriteStart with the derivative of the function. Rewrite the quotient as a product using a negative exponent.✓ Proved
- \[ = \left(10 x + 3\right) \frac{d}{d x} \frac{1}{5 x - 4} + \frac{\frac{d}{d x} \left(10 x + 3\right)}{5 x - 4} \]productApply the product rule.✓ Proved
- \[ = \left(10 x + 3\right) \frac{d}{d x} \frac{1}{5 x - 4} + \frac{10}{5 x - 4} \]derivativeDifferentiate the first part of the product.✓ Proved
- \[ = \frac{\left(- 10 x - 3\right) \frac{d}{d x} \left(5 x - 4\right)}{\left(5 x - 4\right)^{2}} + \frac{10}{5 x - 4} \]chainApply the chain rule to the second part.✓ Proved
- \[ = \frac{5 \left(- 10 x - 3\right)}{\left(5 x - 4\right)^{2}} + \frac{10}{5 x - 4} \]derivativeDifferentiate the innermost function.✓ Proved
- \[ = \frac{10}{5 x - 4} - \frac{50 x + 15}{\left(5 x - 4\right)^{2}} \]algebra algebraSimplify the signs. Rewrite with positive exponents.✓ Proved
- \[ = - \frac{55}{\left(5 x - 4\right)^{2}} \]algebra algebra simplifyCombine the terms over a common denominator. Distribute the constant in the numerator. Combine like terms to get the final answer.✓ Proved
Answer \( - \frac{55}{\left(5 x - 4\right)^{2}} \)
✓ 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 | line 1 is the problem as stated |
| 2 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 undefined where 5*x - 4 = 0 |
| 3 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 undefined where 5*x - 4 = 0 |
| 4 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 undefined where 5*x - 4 = 0 |
| 5 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 undefined where 5*x - 4 = 0 |
| 6 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 undefined where 5*x - 4 = 0 |
| 7 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 undefined where 5*x - 4 = 0 |
| 8 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 undefined where 5*x - 4 = 0 |
| 9 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 undefined where 5*x - 4 = 0 |
| 10 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 undefined where 5*x - 4 = 0 |
| 11 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 undefined where 5*x - 4 = 0 |
| answer | ✓ Proved | sympy 1.14.0 | final line against the stated answer: simplify(a - b) reduced to 0 undefined where 5*x - 4 = 0 |
| answer, a second way | ✓ Proved | sympy 1.14.0 | SymPy differentiated f directly and got the stated answer |
Reviewers
gpt-oss:20b: passdeepseek-r1:70b: passqwen3.6:27b-mlx: pass
Every verdict on record (13)
qwen3.6:27b-mlx: pass 2026-09-20gpt-oss:20b: pass 2026-09-20qwen3.6:27b-mlx: pass 2026-09-20 — The solution correctly applies the product rule, chain rule, and algebraic simplification steps. Each step isolates a single transformation, and the labels accurately reflect the rules applied.gpt-oss:20b: pass 2026-09-20qwen3.6:27b-mlx: pass 2026-09-19 — The solution correctly applies the product and chain rules, with appropriate labels for each step. The algebraic simplifications are sound and clearly explained.deepseek-r1:70b: pass 2026-09-19gpt-oss:20b: pass 2026-09-19qwen3.6:27b-mlx: pass 2026-09-19 — The solution correctly applies the product and chain rules, with appropriate labels for each step. The algebraic simplifications are sound and clearly explained.deepseek-r1:70b: pass 2026-09-19gpt-oss:20b: pass 2026-09-19qwen3.6:27b-mlx: pass 2026-09-18 — The solution correctly applies the product rule, chain rule, and algebraic simplification. Each step changes only one aspect of the expression and uses valid labels from the fixed vocabulary.deepseek-r1:70b: pass 2026-09-18gpt-oss:20b: pass 2026-09-18
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
gemma4:26b, checked 2026-09-26 with SymPy 1.14.0.