∫Calc Practice

Limit of \( \displaystyle \frac{\tan{\left(x \right)}}{x} \) as \( x \to 0 \)

Problem 1.64 · easy

Evaluate \( \displaystyle \lim_{x \to 0} \frac{\tan{\left(x \right)}}{x} \).
  1. \[ \lim_{x \to 0^+}\left(\frac{\tan{\left(x \right)}}{x}\right) \]
    limitIdentify the limit to be evaluated.✓ Proved
  2. \[ = \lim_{x \to 0^+}\left(\frac{\sin{\left(x \right)}}{x \cos{\left(x \right)}}\right) \]
    rewrite algebraRewrite tan(x) as sin(x)/cos(x). Rearrange the fraction.✓ Proved
  3. \[ = \lim_{x \to 0^+}\left(\frac{\sin{\left(x \right)}}{x}\right) \lim_{x \to 0^+} \frac{1}{\cos{\left(x \right)}} \]
    limit-lawApply the product rule for limits.✓ Proved
  4. \[ = \lim_{x \to 0^+} \frac{1}{\cos{\left(x \right)}} \]
    limitEvaluate the first limit using the fundamental trigonometric limit.✓ Proved
  5. \[ = 1 \]
    limit simplify simplifyEvaluate the second limit by direct substitution. Simplify the numerical expression. Final result.✓ Proved
Answer \( 1 \)

✓ 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
LineStatusChecked byDetail
1✓ Provedsympy 1.14.0line 1 is the problem as stated
2✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
tan has poles at odd multiples of pi/2
undefined where x = 0
undefined where cos(x) = 0
3✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
undefined where cos(x) = 0
undefined where x = 0
4✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
undefined where cos(x) = 0
undefined where x = 0
5✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
undefined where cos(x) = 0
undefined where x = 0
6✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
undefined where cos(x) = 0
7✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
8✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
answer✓ Provedsympy 1.14.0final line against the stated answer: simplify(a - b) reduced to 0
answer, a second way✓ Provedsympy 1.14.0SymPy took the limit from both sides and got the stated value

Reviewers

  • gpt-oss:20b: pass
  • qwen3.6:27b-mlx: pass
Every verdict on record (4)
  • qwen3.6:27b-mlx: pass 2026-10-03
  • gpt-oss:20b: pass 2026-10-03
  • qwen3.6:27b-mlx: pass 2026-09-30 — The solution correctly applies standard limit laws and trigonometric identities. Each step changes only one aspect of the expression and uses an acceptable label from the fixed vocabulary.
  • gpt-oss:20b: pass 2026-09-30

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 2026-10-03 with SymPy 1.14.0.