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The sequence of numbers.

Source: licencja: CC 0.

Pojęcie ciągu

Learning objectives

You will get to know the method of describing the properties of the sequence of numbers.

You will get to know the method of finding the terms of the sequence.

Learning effect

  • You will learn to describe the properties of the sequence of numbers.

  • You will learn how to find the terms of the sequence.

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nagranie abstraktu

Recollect all that you know about the functionfunctionfunction. Complete the sentences.

a) The function is an association in which [tu uzupełnij].
b) The domain of a function is [tu uzupełnij].
c) The set of outputs of a function is [tu uzupełnij].
d) The function can be described in many ways [tu uzupełnij].
e) The graph of a function is [tu uzupełnij].
a) The function is an association in which [tu uzupełnij].
b) The domain of a function is [tu uzupełnij].
c) The set of outputs of a function is [tu uzupełnij].
d) The function can be described in many ways [tu uzupełnij].
e) The graph of a function is [tu uzupełnij].

The aim of the class will be getting to know the properties of the functionfunctionfunction whose domain are positive natural numbersnatural numbersnatural numbers. This type of a functionfunctionfunction is called a sequencesequencesequence. Use the available sources to find the definition of the sequencesequencesequence.

sequence
Definition: sequence
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nagranie abstraktu

The sequence of numberssequence of numberssequence of numbers is a functionfunctionfunction defined in a set of positive natural numbersnatural numbersnatural numbers. The outputs of this functionfunctionfunction for consecutive natural numbersnatural numbersnatural numbers are called the terms of a sequencesequencesequence and denoted by (aIndeks dolny n).

Task 1
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nagranie abstraktu

Think about the methods of describing sequencesmethods of describing sequencesmethods of describing sequences. Think how to describe a sequencesequencesequence. Remember that the sequencesequencesequence is a functionfunctionfunction. Formulate your conclusion.

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nagranie abstraktu

Conclusion:

The sequencesequencesequence, just like any functionfunctionfunction, can be described by words, a table, a formula, a graph or ordered pairs.

Analyse the graphs of sequences.

Task 2
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Aplet geogebry - Pojęcie ciągu. Poniżej znajduje się galeria będąca wersją alternatywną dla aplikacji.
Source: GroMar, licencja: CC BY 3.0.
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nagranie abstraktu

Analyse the material presented in the applet. Sketch the fragments of the graphs of sequences in the given formulas.

  1. aIndeks dolny n = 3 - n

  2. aIndeks dolny n = -4 + 2n

  3. aIndeks dolny n = (-1)Indeks górny n - n

  4. aIndeks dolny n = 2n - 2Indeks górny n

  5. aIndeks dolny n = nIndeks górny 2 - 2n +3

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nagranie abstraktu

What have you observed? Formulate your conclusion.

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nagranie abstraktu

Conclusion:

The graph of a sequencesequencesequence is drawn in the same way as the graph of an appropriate functionfunctionfunction. The graph is not a line, but a set of points.

Use the information to do the tasks individually.

Task 3
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nagranie abstraktu

Calculate the four initial terms of sequencesequencesequence (an) and term a11.

  1. an=n2n+2

  2. an=-2n(n+3)

  3. an=n4-n3

Task 4
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nagranie abstraktu

Draw the graph of sequencesequencesequence aIndeks dolny n = 2n - 1 knowing that n ∈ N and 1 ≤ n ≤ 10.

Task 5
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nagranie abstraktu

An extra task:

Check, which terms of sequencesequencesequence an=n+13n-2 are integer numbers.

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nagranie abstraktu

Having finished all the tasks, do the consolidation tasks.

Remember:

Exercises

Exercise 1
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Wersja alternatywna ćwiczenia: Determine which sentences are true. Możliwe odpowiedzi: 1. The second term of a sequence an=24-4nn is 7., 2. The third term of a sequence an=2-6n is a natural number., 3. The seventh term of a sequence an=n2-4n-21n+1 equals zero., 4. The second term of a sequence an=n2+11n+8n equals 18.
zadanie
Source: GroMar, licencja: CC BY 3.0.
Exercise 2

Sketch the graph of sequence an=-nn+2, n∈NIndeks dolny +.

Exercise 3

Describe in English the methods of describing sequencesmethods of describing sequencesmethods of describing sequences.

Exercise 4
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Wersja alternatywna ćwiczenia: Indicate which pairs of expressions or words are translated correctly. Możliwe odpowiedzi: 1. ciąg - sequence, 2. ciąg liczbowy - sequence of numbers, 3. sposoby opisywania ciągów - methods of describing sequences, 4. liczby naturalne - natural numbers, 5. ciąg - function, 6. liczby naturalne - sequence of numbers
zadanie
Source: GroMar, licencja: CC BY 3.0.
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Interaktywna gra, polegająca na łączeniu wyrazów w pary w ciągu jednej minuty. Czas zaczyna upływać wraz z rozpoczęciem gry. Jeden ruch to odkrywanie najpierw jednej potem drugiej karty z wyrazem. Każdy wyraz jest odczytywany. Kolejny ruch to odkrywanie trzeciej i czwartej karty. W ten sposób odsłuchasz wszystkie wyrazy. Nawigacja z poziomu klawiatury za pomocą strzałek, odsłuchiwanie wyrazów enterem lub spacją. Znajdź wszystkie pary wyrazów.
Source: Zespół autorski Politechniki Łódzkiej, licencja: CC BY 3.0.

Glossary

function
function

funkcja

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wymowa w języku angielskim: function
methods of describing sequences
methods of describing sequences

sposoby opisywania ciągów

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wymowa w języku angielskim: methods of describing sequences
natural numbers
natural numbers

liczby naturalne

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wymowa w języku angielskim: natural numbers
sequence
sequence

ciąg

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nagranie abstraktu
sequence of numbers
sequence of numbers

ciąg liczbowy

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wymowa w języku angielskim: sequence of numbers

Keywords

functionfunctionfunction

methods of describing sequencesmethods of describing sequencesmethods of describing sequences

natural numbersnatural numbersnatural numbers

sequencesequencesequence

sequence of numberssequence of numberssequence of numbers