Предмет: Математика, автор: leraafd

У геометричній прогресії b1=0,25, q=2. Знайдіть b10 i S=10​

Ответы

Автор ответа: MatemaT123
1

Ответ:

128; \quad 255,75;

Пошаговое объяснение:

b_{n}=b_{1} \cdot q^{n-1};\quad b_{10}=b_{1} \cdot q^{9}; \quad b_{10}=0,25 \cdot 2^{9}=2^{-2} \cdot 2^{9}=2^{-2+9}=2^{7}=128;

S_{n}=\dfrac{b_{1}(1-q^{n})}{1-q}; \quad S_{10}=\dfrac{0,25(1-2^{10})}{1-2}=\dfrac{-1023:4}{-1}=255,75;

leraafd: спасибо)
MatemaT123: Пожалуйста)
Предыдущий вопрос
Следующий вопрос
Похожие вопросы
Предмет: Английский язык, автор: maks9pa
Помогите сделать задания вот текст и к тексту задания
LONDON
London is the capital of the United Kingdom, its economic, political and cultural centre. It’s one of the world’s most important ports and one of the largest cities in the world. London with its suburbs has a population of about 11 million people.
London has been a capital for nearly a thousand years. Many of its ancient buildings still stand. The most famous of them are the Tower of London, where the crown jewels are kept, Westminster Abbey and St. Paul’s cathedral. Most visitors also want to see the Houses of Parliament, Buckingham Palace (the Queen’s house with its changing of the Guards) and a lot of magnificent museums.
Once London was a small Roman town on the north bank of the Thames. Slowly it grew into one of the world’s major cities.
Different areas of London seem like different cities. The West End is a rich man’s world of shops, offices and theatres. The city of London is the district where most offices and banks are concentrated; the Royal Exchange and the Bank of England are here, too. The East End is the district where mostly working people live. The old port area is now called “Docklands”. There are new office buildings in Docklands, and thousands of new flats and houses.
By the day the whole London is busy. At night, offices are quiet and empty, but the West End stays alive, because this is where Londoners come to enjoy themselves. There are two opera-houses here, several concert-halls and many theatres, as well as cinemas. In nearby Soho the pubs, restaurants and night clubs are busy half the night.
Like all big cities, London has streets and concrete buildings, but it also has many big parks, full of trees, flowers and grass. In the middle of Hyde Park or Kensington Gardens you will think that you are in the country, miles away.
Many people live outside the centre of London in the suburbs, and they travel to work in shops and offices by train, bus or underground (“The Tube”).

II. Consult the encyclopedia and find the derivation of the name “London”.
III. Make sentences with each of the words below.
suburbs ancient jewels
magnificent major areas
district banks docklands

IV. Say whether it is true or false.
1. London has a history of more than 20 centuries.
2. St. Paul’s Cathedral is one of the most famous ancient buildings of London.
3. The population of London is about 10 million people.
4. London lies on the river Severn.
5. The Royal Exchange and the Bank of England are situated in the City.
6. Soho is the district with pubs, restaurants and night clubs which are busy half the night.
7. Most of people live outside the centre of London.
1 год назад
Предмет: Русский язык, автор: Leyla096
Синтакс.разбор предлодений:
Осень.Обсыпается весь наш бедный сад.
Листья пожелтелые по ветру летят;
Лишь в дом красуются там на дне долин,кисти ярко-красные вяжащих рябин.
Помогите пжл
1 год назад
Предмет: Другие предметы, автор: Marta20051996
Переставьте 1 спичку так, что бы ответ был равен 30
8+7+6+15=30
1 год назад
Предмет: Окружающий мир, автор: zabiaka74
Охрана окружающей среды Приморского края 4 класс кратко
7 лет назад
Предмет: Математика, автор: kristinaMalnik
Можно по действиям срочно
7 лет назад