Предмет: Алгебра, автор: buha19

найдите сумму всех четных трехзначных чисел

Ответы

Автор ответа: kmike21

множество четыпехзначных чисел можно рассматривать как арифметичесую прогрессию, где a₁=1000, $a_{9000}=9999$
надо найти
$S_{9000}= \frac{a_1+a_{9000}}{2}*9000=\frac{1000+9999}{2}*9000= 49495500$

buha19: четных трехзначных?

Предыдущий вопрос

Следующий вопрос

Похожие вопросы

Предмет: Қазақ тiлi, автор: AluaBolat

Рухани жанғыру туралы эссе

2 года назад

Предмет: Русский язык, автор: DEN342295

Замените словосочетание "Берётся за спасение " , построенное на основе управления, синонимичным словосочетанием со связью ПРИМЫКАНИЕ. Напишите получившееся словосочетание.

2 года назад

Предмет: Английский язык, автор: Oksana2342

Помогите пожалуйста, СРОЧНО!!! Сократить текст(сжато), для пересказа)))

The National Health Service provides free treatment for people living in Britain and gives emergency treatment for visitors. The greater part of the cost is met from taxes taken from people’s wages. People also pay some money every month as a sort of insurance.
The National Health Service consists of three main parts: the general practitioners, the hospital and specialist services, and local health authority services. Local health authorities are responsible for medical education, hospital building, environmental health, vaccination service and so on.
The centre of National Health Service is the general practitioner (GP). Each person is registered with a certain doctor in his or her area. The GP diagnoses, gives medical certificates, prescribes medicines. Dentists and opticians usually have separate clinics. They are not parts of health centres.
There is also a medium-level hospital staff. District nurses give injections, physiotherapy exercises at people’s homes. Ward nurses take care of the ill in the hospital.
Regular medical inspections are held at schools. Children receive various vaccinations and are examined by different specialists. There also exists a school dental service in every school.
Much attention is paid to the educational programmes. The Department of Health provides anti-smoking education programmes, alcohol education programmes, cancer prevention programmes and so on. Much attention is paid to the AIDS and drug programmes.
Great Britain pays much attention to the qualification of doctors. They are trained at 16 universities. Besides, they get practice during their work at teaching hospitals.