Derivative at a point
A derivative is a finite limit of local difference quotients.
Key knowledge
For a real function defined on an open interval around a, its derivative at a is the limit of [f(a+h)−f(a)]/h as h approaches zero, if that finite limit exists.
Values and equations
f′(a) = limₕ→₀ [f(a+h) − f(a)]/h
- f
- Real-valued function near a
- a
- Point of differentiation
- h
- Nonzero input increment tending to zero
- f′(a)
- Derivative when the finite limit exists
Conditions and scope
- The quotient uses h ≠ 0; both sides must approach the same finite value.
- If f and its input are measured quantities, the derivative has output units per input unit.
Sources · 3
References
Sources retain their recorded scope. A source link alone does not establish verification of every statement.
Evidence and review
Difference-quotient definition and rate interpretation.
2026-10-10 · Checked limit existence and local-domain conditions.
Foundational review
2026-10-10 · Fresh primary-source inspection of the complete compact record, including every statement, equation, quantity and material condition, followed by independent AI editorial review. This check does not certify all linked lessons or every passage of every cited publication.
Sources from other places
Scope or convention differs
Two-sided difference-quotient derivative at an interior point.
The source also discusses infinite tangent slopes; the repository restricts its derivative to a finite limit.
Universidade de São Paulo, Instituto de Matemática e Estatística
- Cálculo I · Agenda 09: Derivadas BrazilPortuguese
§3, Definitions 2–3, pp.6–7; §1 pp.1–2
- Cálculo I · Agenda 09: Derivadas
Entry details
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- math-derivatives
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