Выписаны первые несколько членов геометрической прогрессии: 5; -10; 20; ... Найдите сумму - №11334305

Выписаны первые несколько членов геометрической прогрессии: 5; -10; 20; ...
Найдите сумму первых пяти её членов.
- Предмет:
  Алгебра
- Автор:
  chief95
- 6 лет назад

Ответы 1

Sn=b1*(q^n-1)/q-1 q=b2/b1 q=-10/5;q=-2 S5=5*((-2)^5-1)/-2-1;S5=-165/-3;S5=55
- Автор:
  davinjefferson
- 6 лет назад
- 0
Добавить свой ответ

Еще вопросы

Помогите пожалуйста перевести текст...

Dear Maria
Thanks for you letter. I'm glad to hear that everything Is going well. I'm sorry i haven't written for so long but i've been really bysy looking out for a summer job.

You asked me about my plans for summer holidays. Well, now i'm working in a camp shop. I'm glad that i've got this job, because i've always wanted to be in a 'people' type of job. I like meeting new people, helping and tallking to them. I think that working at the camp helps me to learn now to be responsible for a lot of different things. If people complain, I know how to deal with them. I'm getting long of valuable practical expreriense that may be useful for the future. As you know, I want to go on to study business and law at university. One of my favourite parts of working Is belonging to a team and meeting people from lots of different places. I'm usually at work from about 9 am until 5 pm and I check people in and serve holidaymakers. I enjoy working at the camp - everyon knows who I am and I know them!

Do you work during the holiday season? Will this job help you in your future carrer? Are summer jobs popular with teenagers in you country?

Write back soon.
Emma
- Предмет:
  Английский язык
- Автор:
  jabarimiddleton
- 6 лет назад
- Ответов:
  
  4
- Смотреть
Из двух пунктов , расстояние между которыми равно 34,69 км одновременно навстречу друг другу вышли два пешехода . Скорость первого равна 4,8км/ч а скорость второго 5,4км/ч . Через сколько часов они встретятся .
- Предмет:
  Математика
- Автор:
  barclay
- 6 лет назад
- Ответов:
  
  2
- Смотреть
сожгли 235,8л CH2,содержащего 5% примессей.полученный CO2 пропустили через известковую воду.найдите массу осадка
- Предмет:
  Химия
- Автор:
  brookefwrb
- 6 лет назад
- Ответов:
  
  0
- Смотреть
Откройте скобки. Great Iron chest part 3. When the princess saw the young man, she (1.like) him very much. She (2.begin)(3.work) as hard as she (4.can). She (5.think) she never (6.see) anyone so handsome. She (7.know) she (8.make) him free soon. And she (9.do). The Prince (10.take) her hand and (11.say) he (12.be) under the spell all those years. He (13.suffer) a lot. He (14.thank) the Princess as she (15.save) him.
He (16.tell) her he (17.want) them (18.go) to his father's kingdom and (19.expect) her (20.marry) him. The Princess (21.agree) because she already (22.fall) in love with the young man. But she (23.ask) him (24.let) her (25.go) first to his father's palace and (26.say) goodbye to her old father. The Princess (27.agree) though he (28.look not) pleased. He (29.want) the Princess (30.speak) no more than three words to her father and then (31.come) back to him immediately.
- Предмет:
  Английский язык
- Автор:
  nikkivewy
- 6 лет назад
- Ответов:
  
  1
- Смотреть

How much to ban the user?

1 hour 1 day 100 years