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Arithmetic and geometric sequence - applications

Source: licencja: CC 0.

Ciąg arytmetyczny i geometryczny - zastosowania

Learning objectives

  • You will learn how to calculate the terms of the arithmetic and geometric sequences with given relationships and dependencies between these terms.

  • You will learn how geometric and arithmetic sequences are used to solve practical problems.

Learning effect

  • You calculate the values of terms of arithmetic and geometric sequences on the basis of relationships and dependencies between them.

  • You use the properties of arithmetic and geometric sequences to solve practical problems.

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nagranie abstraktu

Review your knowledge of arithmetic and geometric sequences.

Complete the sentences:

  • Sequence (aIndeks dolny n) is called an arithmetic sequencearithmetic sequencearithmetic sequence if ...

  • The arithmetic sequence (aIndeks dolny n) is increasing if ...

  • To calculate the sum of n initial terms of the arithmetic sequencearithmetic sequencearithmetic sequence, ...

  • geometric sequencegeometric sequencegeometric sequence is a number sequence (aIndeks dolny n), in which ...

  • The sum of the n initial terms of the geometric sequence (aIndeks dolny n) with the quotient q ≠ 1 is calculated according to the formula ...

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nagranie abstraktu

The aim of the lesson is to use the previously learned formulas associated with the arithmetic sequencearithmetic sequencearithmetic sequence and formulas associated with the geometric sequencegeometric sequencegeometric sequence.

Task 1
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nagranie abstraktu

Watch and analyze the Slideshow, showing how to solve the task using the properties of sequences.

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Pokaz slajdów – Sposób rozwiązania zadania z wykorzystaniem własności ciągów. Instrukcja obsługi z poziomu klawiatury: 1. Uruchomienie aplikacji - ENTER, 2. Na każdym ze slajdów czytany jest automatycznie tekst alternatywny po polsku, 3. Przy pierwszym uruchomieniu na pierwszym slajdzie, czytanie tekstu po angielsku - TAB, 4. Przejście między slajdami: do następnego slajdu - TAB, do poprzedniego slajdu - TAB + SHIFT, 5. Przejście do czytania napisu po angielsku - strzałka w górę + strzałka w dół (czyta tekst po angielsku widoczny na slajdzie).
Source: GroMar, licencja: CC BY 3.0.
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nagranie abstraktu

When solving tasks involving arithmetic and geometric sequences, the properties of both sequences should be used simultaneously.

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nagranie abstraktu

Students work independently and solve tasks.

Task 2
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nagranie abstraktu

Between numbers 2 and 30, insert two numbers in such a way that the first three numbers form a geometric sequencegeometric sequencegeometric sequence, and the last three form an arithmetic sequencearithmetic sequencearithmetic sequence.

Task 3
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nagranie abstraktu

The following numbers are presented: 3, x, y, 25. The first three form an increasing arithmetic sequencearithmetic sequencearithmetic sequence, the last three - a geometric sequencegeometric sequencegeometric sequence. Calculate x and y.

Task 4
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nagranie abstraktu

A bacteriologist studying the growth of bacterial cells found that the bacteria on the agar plate doubled their number every 10 minutes. Assuming the initial sample contained 100 bacteria, calculate the number of microorganisms after 4 hours of culture.

Task 5
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nagranie abstraktu

The ball thrown from the balcony of the apartment located on the second floor of the building bounces many times off the concrete ground of the yard. After each consecutive bounce, it loses some energy and rises to 23 of the previous height. Calculate the path in the vertical (up and down) of the ball to the fourth bounce, knowing that the second floor of the building is located 9 meters above the yard’s surface.

Task 6

An extra task:

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nagranie abstraktu

The cuboid edge lengths form a geometric sequencegeometric sequencegeometric sequence. The volume of this cuboid is equal to 1000 cmIndeks górny 3 and the total surface area is 700 cmIndeks górny 2. Calculate the edge lengths of the cuboid.

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nagranie abstraktu

Do the revision exercises.

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nagranie abstraktu

When solving tasks that involve arithmetic and geometric sequences, the properties of both sequences should be used simultaneously.

Exercises

Exercise 1
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Wersja alternatywna ćwiczenia: Determine which sentences are true. Możliwe odpowiedzi: 1. If the lengths of the sides of equilateral triangles form an arithmetic sequence, then the areas of these triangles also form an arithmetic sequence., 2. The sum of all even two-digit numbers is equal to 2430., 3. If the numbers (9, x, x-2), in the order given, form a decreasing geometric sequence, then x=3 lub x=6., 4. If the measures of angles of a right triangle form an arithmetic sequence, then the difference in the sequence is equal to 45°.
zadanie
Source: GroMar, licencja: CC BY 3.0.
Exercise 2

The ball rolling on an inclined plane in the first second traveled the length of 0,25 m and in every next second the path was 0,5 m longer than the previous one. Calculate the length of the path that the ball traveled during the 15 seconds.

Exercise 3

The lengths of the sides of a right triangle form an arithmetic sequence. The hypotenuse is 20 feet long.

Describe in English how you can calculate the area of this triangle.

Exercise 4
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Wersja alternatywna ćwiczenia: Indicate which pairs of expressions or words are translated correctly. Możliwe odpowiedzi: 1. ciąg arytmetyczny - arithmetic sequence, 2. ciąg geometryczny - geometric sequence, 3. iloraz ciągu geometrycznego - quotient of the geometric sequence, 4. różnica ciągu arytmetycznego - difference of the arithmetic sequence, 5. własności ciągu geometrycznego - properties of arithmetic sequence, 6. różnica ciągu arytmetycznego - quotient of the geometric sequence
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

arithmetic sequence
arithmetic sequence

ciąg arytmetyczny

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wymowa w języku angielskim: arithmetic sequence
difference of the arithmetic sequence
difference of the arithmetic sequence

różnica ciągu arytmetycznego

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wymowa w języku angielskim: difference of the arithmetic sequence
geometric sequence
geometric sequence

ciąg geometryczny

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wymowa w języku angielskim: geometric sequence
properties of arithmetic sequence
properties of arithmetic sequence

własności ciągu arytmetycznego

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wymowa w języku angielskim: properties of arithmetic sequence
properties of geometric sequence
properties of geometric sequence

własności ciągu geometrycznego

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wymowa w języku angielskim: properties of geometric sequence
quotient of the geometric sequence
quotient of the geometric sequence

iloraz ciągu geometrycznego

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wymowa w języku angielskim: quotient of the geometric sequence
sum of the initial terms
sum of the initial terms

suma początkowych wyrazów

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wymowa w języku angielskim: sum of the initial terms
sum of the initial terms of arithmetic sequence
sum of the initial terms of arithmetic sequence

suma początkowych wyrazów ciągu arytmetycznego

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wymowa w języku angielskim: sum of the initial terms of arithmetic sequence
sum of the initial terms of geometric sequence
sum of the initial terms of geometric sequence

suma początkowych wyrazów ciągu geometrycznego

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wymowa w języku angielskim: sum of the initial terms of geometric sequence

Keywords

arithmetic sequencearithmetic sequencearithmetic sequence

difference of the arithmetic sequencedifference of the arithmetic sequencedifference of the arithmetic sequence

geometric sequencegeometric sequencegeometric sequence

quotient of the geometric sequencequotient of the geometric sequencequotient of the geometric sequence

sum of the initial termssum of the initial termssum of the initial terms