Calculus, grade 11 (5 units)
The derivative says how fast a function changes; in this course you also ask how that rate itself changes, and investigate new families of functions.Subjects
The course builds on the calculus of grade 10: the rules of differentiation, the tangent line, investigating a function, the square root function and the rational function. The topics, in order:
- how the rate of change changes: concavity, the second derivative, inflection points, the second derivative and the type of an extremum, the graphs of , and , acceleration and real-life problems;
- rational functions: their behaviour near the points where they are not defined and at the ends of the domain, a full investigation with concavity, families with a parameter and tangent problems;
- functions with square roots: the domain, different asymptotes at and at , the derivative, equations with a root, investigation, and the graph of from the graph of ;
- extremum problems on a closed and on an open interval, with graphs, in geometry and in solids;
- the trigonometric functions in radians: their properties and graphs, the derivatives of , and , tangents, investigation and extremum problems.
Two kinds of lessons:
- learning lessons – an explanation, solved examples and a few questions to try;
- practice lessons – questions only.
How the page works: Using a page.
- Recap: the calculus of grade 10LearningWhat you learnt in grade 10: the rules of differentiation, the tangent line, investigating a function with a table of signs, the square root function and the rational function – the domain and asymptotes.
- Concavity: how the rate of change changesLearningWhere the slope of the graph grows the graph is concave up, where it shrinks concave down; the tangents and chords of a concave graph; a fall that grows steeper.
- The second derivative and concavityLearningThe second derivative – the rate of change of the derivative; its sign gives the concavity; the intervals of concavity of a polynomial and of a rational function.
- Inflection pointsLearningA point where the function changes its concavity; possible points – $f''=0$ or $f''$ not defined; a horizontal, a slanted and a vertical inflection; $f''=0$ with no inflection; every cubic has one inflection point.
- The second derivative and the type of an extremumLearningWhere $f'=0$: $f''>0$ – a minimum, $f''<0$ – a maximum; the rule works one way, and $f''=0$ gives no conclusion; other ways to tell the type of an extremum; a family with a parameter.
- The graphs of f, f′ and f″LearningWhat the graph of the derivative and the graph of the second derivative tell about the function: rising, extremum points, concavity and inflection; an extremum point of $f'$ is an inflection point of $f$; which graph is the function, which the derivative and which the second derivative.
- The rate of change of a rateLearningDistance, speed and acceleration – $a(t)=v'(t)=s''(t)$; prices that rise more slowly; the length of the day in Tel Aviv – when it grows fastest; filling a vessel; the fastest growth at the inflection point.
- Practice: the second derivativePracticeSecond derivatives, intervals of concavity, inflection points, the type of an extremum from $f''$, the graph of the derivative, acceleration and a family with a parameter.
- Rational functions near undefined points and at the endsLearningThe sign of a rational function on each side of a vertical asymptote, a horizontal asymptote by the degrees, approaching it from above or from below, a graph that crosses its horizontal asymptote, and a removable discontinuity.
- A full investigation of a rational functionLearningThe steps of an investigation with the second derivative: concavity and inflection points; x/(x²+1) with three inflection points; 1/(x²−1), whose concavity changes across its asymptotes with no inflection point; the oxygen in a lake.
- Rational functions: parameters and tangentsLearningA family of rational functions with a parameter – the parameter from an extremum point, the values with no extremum; the tangent at a point of the graph and tangents with a given slope; the asymptotes of a shifted graph.
- Practice: rational functionsPracticeAsymptotes and holes, inequalities, the second derivative and concavity, inflection points, tangents, a parameter, an extremum problem and a function from its graph.
- Functions with square roots: the domain and asymptotesLearningThe domain of a function with a root in a sum, a product, a numerator or a denominator; √(x²) = |x|; a function with different horizontal asymptotes at ∞ and at −∞, or with one on one side only; a vertical asymptote at the end of the domain.
- Derivatives of functions with roots, and root equationsLearningThe derivative of a product and of a quotient with a root, a vertical tangent at the end of the domain, equations with a root – squaring and checking every solution – and the mistake of taking x into the root.
- Investigating functions with square rootsLearningA full investigation of a function with a root, the second derivative included: x√(4−x²) – extremum points inside the domain and at its ends, and an inflection point; x/√(x²+1) – rising throughout, two asymptotes and an inflection point.
- The graph of √f(x) from the graph of fLearningWhat the graph of g(x) = √f(x) takes from the graph of f: the domain where f ≥ 0, the same zeros, extremum points at the same x inside the domain, vertical tangents at the zeros, where √f is above f and where below, and the asymptotes.
- Practice: functions with square rootsPracticeDomains, derivatives with roots, an equation with a root, two asymptotes, investigations with extremum points at the ends and an inflection point, a tangent, √f from f, the nearest point of a graph and a graph to recognise.
- Extremum problems on a closed and an open intervalLearningThe greatest and least values of a function on a closed interval – the extremum points and the ends of the interval; on an open interval there may be no such value; the point of a graph nearest a point; the scouts' camps – the shortest and the longest run.
- Extremum problems in geometry and solidsLearningA rectangle inscribed in a semicircle, a cylinder of given volume with the least surface area, a box from a sheet, a right-angled triangle with a given hypotenuse, the cost of a journey on a closed interval.
- Practice: extremum problemsPracticeThe greatest and least values on a closed and on an open interval, the shortest distance from a point to a graph, a fence by a wall, an open cylinder, a rectangle in a semicircle, the shortest way via a river.
- The trigonometric functions in radiansLearningRadians, the graphs of sine, cosine and tangent, the period, even and odd, zeros and asymptotes; shifts and stretches: y = a·sin(bx+c)+d; a period and the smallest period.
- The derivatives of the trigonometric functionsLearningThe limit of sin x over x, the derivative of sine by the definition, why radians, the derivatives of cosine and tangent, the chain rule and the tangent line.
- Investigating trigonometric functionsLearningAn investigation on an interval of one period: the derivative, the second derivative, extremum points, concavity and inflection points; x + 2sin x; √(sin x) and extremum points at the ends of the domain; the family y = sin x + ax; x²·sin x and its envelope.
- Extremum problems with trigonometric functionsLearningAn angle as the variable: the area of an isosceles triangle without a derivative, a trapezoid inscribed in a semicircle, a rectangle in a semicircle, a Ferris wheel – when the car rises fastest, a gutter with the greatest cross-section, a rectangle with a given diagonal.
- Practice: trigonometric functionsPracticeDerivatives of trigonometric functions, the tangent line, extremum and inflection points on an interval of a period, the period and the values, the second derivative, an extremum problem, √(cos x).
- Course reviewPracticeQuestions from the whole course: the second derivative, concavity and inflection points, the second derivative and the type of an extremum, the graph of f′, investigating a rational function and a function with a root, a tangent, an extremum problem and trigonometric functions.
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