Antiderivatives with initial conditions
Problem 3.434 · medium
Solve the initial-value problem \( \displaystyle f'(x) = - 5 x^{2} + 4 \sin{\left(x \right)} \), \( \displaystyle f(0) = 6 \).
- \[ \frac{d}{d x} \left(- \frac{5 x^{3}}{3} - 4 \cos{\left(x \right)}\right) = - 5 x^{2} + 4 \sin{\left(x \right)} \]An antiderivative; every other differs by a constant C.✓ Proved
- \[ 6 - \left. - \frac{5 x^{3}}{3} - 4 \cos{\left(x \right)} \right|_{\substack{ x=0 }} = 10 \]f(0) = 6 fixes C.✓ Proved
- \[ - \frac{5 x^{3}}{3} - 4 \cos{\left(x \right)} + 10 \]The solution.✓ Proved
Answer \( f(x) = - \frac{5 x^{3}}{3} - 4 \cos{\left(x \right)} + 10 \)
✓ 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 |
| 2 | ✓ Proved | sympy 1.14.0 | simplify(lhs - rhs) reduced to 0 |
| 3 | ✓ 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 | the answer differentiated back to the given derivative, and the initial values checked |
Reviewers
gpt-oss:20b: passqwen3.6:27b-mlx: pass — The solution correctly identifies the antiderivative and determines the constant of integration using the initial condition. The steps are logically sound and algebraically correct.
Every verdict on record (4)
qwen3.6:27b-mlx: pass 2026-10-05 — The solution correctly identifies the antiderivative and determines the constant of integration using the initial condition. The steps are logically sound and algebraically correct.gpt-oss:20b: pass 2026-10-05qwen3.6:27b-mlx: pass 2026-10-05 — The solution correctly identifies the antiderivative, calculates the constant of integration using the initial condition, and states the final result. The logic is sound.gpt-oss:20b: pass 2026-10-05
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/antiderivative_ivp, checked 2026-10-05 with SymPy 1.14.0.