AP Calculus · Unit 5
Analyzing Functions
Extrema, concavity and optimization.
Topic 5.1Use the mean value theorem
- Check when the theorem appliesVerify continuity on the closed interval and differentiability throughout its interior.
- Find every matching pointCalculate the average rate, solve the derivative equation, and keep every solution inside the interval.
- Use a graph or table to identify a guaranteeCombine the supplied data with explicitly stated conditions; do not infer continuity from a few readings.
- Apply the theorem to a real situationMatch an instantaneous rate with an average rate and report the time or input with units.
- Distinguish existence from uniquenessSelect what the theorem guarantees. Recognize when you need more information to claim exactly one point.
Topic 5.2Extrema, critical points and guarantees
- Find critical numbers in the domainInclude zeros and undefined derivatives only where the function itself is defined.
- Distinguish local and absolute extremaIdentify whether a value is best nearby or over the whole specified domain.
- Check the Extreme Value Theorem conditionsVerify continuity on a closed bounded interval without requiring differentiability.
- Recognize when a maximum or minimum does not existDistinguish an approached bound from an actual minimum or maximum.
- Do not classify from a zero derivative aloneRecognize stationary points and corners that may or may not be extrema.
Topic 5.3Increasing and decreasing intervals
- Find where the derivative's sign can changeLocate derivative zeros, undefined derivatives, and breaks in the function's domain.
- Determine derivative signs on intervalsUse a formula, sign chart, or derivative graph correctly.
- State increasing and decreasing intervalsTranslate the derivative's sign into correctly notated intervals.
- Handle zeros without a sign changeRecognize that a flat point does not necessarily reverse the function's direction.
Topic 5.4Classify turning points with signs
- Identify candidates for local extremaFind relevant critical points and respect domain restrictions.
- Test the derivative on both sidesDetermine whether the sign changes from positive to negative, negative to positive, or neither.
- Classify a candidate using the sign changeIdentify a local maximum, local minimum, or neither.
- Report the requested location or pointDistinguish the input coordinate from the function value and full point.
Topic 5.5Find absolute extrema
- Find all candidates on the intervalInclude endpoints and every interior critical point where the function is defined.
- Compare function valuesEvaluate the original function at all candidates, including nondifferentiable points.
- Report absolute extrema in fullIf the question asks, give both the extreme value and the input where it occurs.
- Justify that the search is completeUse the interval conditions and candidate method or an equivalent supported argument.
- Recognize an unattained extremumHandle open endpoints or missing points without inventing a minimum or maximum.
Topic 5.6Concavity and inflection
- Determine concavity on intervalsUse the sign of the second derivative or whether the first derivative is increasing or decreasing.
- Find candidate inflection locationsInclude zeros and undefined second derivatives while checking the function's domain and continuity.
- Verify a change in concavityRequire an actual change instead of treating a zero second derivative as sufficient.
- Report an inflection pointIf the question asks for coordinates, find the function value as well as the input.
- Handle an undefined second derivativeRecognize a valid inflection point when concavity changes even though the second derivative does not exist.
Topic 5.7Use the second derivative test
- Check that the point is stationaryVerify that the first derivative is zero before applying the second derivative test.
- Evaluate the second derivativeCalculate its value at the candidate point.
- Classify a positive or negative resultIdentify a local minimum from a positive result and a local maximum from a negative result.
- Handle an inconclusive resultWhen the test gives zero or is unavailable, use first-derivative signs or nearby values to determine actual behavior.
Topic 5.8Sketch a function and its derivative
- Read derivative values from a function graphTranslate tangent slopes into derivative values and identify corners where the derivative is absent.
- Read function direction from a derivative graphUse derivative heights to find increasing and decreasing intervals and turning points.
- Read concavity from a derivative graphUse whether the derivative graph rises or falls, separately from whether it is above the axis.
- Match a function with its derivativeSelect compatible graphs or graph features from the supplied alternatives.
- Build a function from graph conditionsEnter a formula or point satisfying supplied slope, vertex, and height constraints in an explicitly bounded construction task.
Topic 5.9Connect f, f′ and f″
- Identify which function a graph representsDistinguish the roles of f, its first derivative, and its second derivative.
- Connect signs with direction and concavityInfer increase or decrease from the first derivative and bending from the second.
- Connect zeros with candidate featuresDistinguish function zeros, stationary points, and possible inflection points.
- Choose conclusions supported by the available informationRecognize when derivative data does not determine the function's absolute height.
- Combine several pieces of derivative evidenceSelect a consistent description or reconstruct a supported formula from the given conditions.
Topic 5.10Build an optimization model
- Identify the quantity to optimizeDistinguish the objective, such as cost or area, from the constraint.
- Write the constraintTranslate the geometric or contextual restrictions into an equation.
- Build an objective in one variableSubstitute the constraint to remove extra variables.
- State the feasible domainInclude physical restrictions and distinguish allowed boundary cases from impossible ones.
Topic 5.11Solve and justify an optimum
- Build the objective and its domainWrite a correct one-variable model for the situation.
- Find feasible candidatesSolve the derivative condition and include relevant endpoints or boundaries.
- Justify the best candidateCompare values or use a valid global sign or monotonicity argument.
- Answer the original questionReport the requested dimensions, input, and optimal value with units.
Topic 5.12Behavior of implicit curves
- Find an implicit first derivativeDifferentiate the relation and solve for the slope.
- Find an implicit second derivativeDifferentiate the first derivative while still treating y as a function of x.
- Determine concavity at a pointEvaluate the second derivative at a valid point and interpret its sign.
- Identify horizontal or vertical tangentsApply the appropriate conditions and check where the derivative formula is inconclusive.