Предмет: Алгебра, автор: rosyKat4yKun3s

Арифметическая прогрессия (а n) задана условиями: а1 = 5, аn + 1 = an - 3. найдите а10 ?

Ответы

Автор ответа: sedinalana

a1=5,an+1=an-3⇒d=-3
a10=a1+9d=5+9*(-3)=5-27=-22

Предыдущий вопрос

Следующий вопрос

Похожие вопросы

Предмет: Химия, автор: Honegyu

1)NH3+O2-t°->N2+H2O
2)NH3+O2-t°,кат—>NO+H2O

Напишите пж схожие и отличительные черты данных реакций пж
Заранее спасибо

6 лет назад

Предмет: Русский язык, автор: snezanai442

Помогите срочно, сейчас!!!

6 лет назад

Предмет: Английский язык, автор: Villiova

Переведите и вставьте правильный вариант (укажите разницу между вариантами)

«Learning to live with the lemur»
When I was three, my family went (on/in) a trip (at/to) London Zoo. My dad still tells the story of the fi rst animal we saw that day. Nobody knew what it was, until, he says, I suddenly screamed “They’re lemurs!” Where, at just three, did I learn lemur? We still have no idea.
Last month I fi nally got a chance to spend time (on/with) these animals – 30 years after surprising my parents in that zoo. I flew (to/in) the island of Madagascar, the home of the lemur. I was visiting a wildlife-conservation project.
When people fi rst arrived on the island, 2,000 years ago, there were hundreds of difference species of lemur. They included the giant lemur – as big as a gorilla, weighing 200 kg. But people hunted the animals and cut down large areas of the lemurs’ forests. The giant lemur became extinct in only a few years. Many other species died for similar reasons. And they are still dying.
Now, there are 70 species of the animal, from the tiny 28 g mouse lemur to the famous ring-tailed lemur I probably saw in that zoo. They now live in an area of 6,000 km2 – just 10% of the island. Fortunately, the country is trying to protect the lemur. Volunteers are working on a variety of projects: from talking to schools (to/about) the environment to actually counting the number of male and female lemurs in the forest. And the project are a success. While I was there, I heard stories (about/aroun) the discovery of a new population of bamboo lemurs unusual species on the island. Scientists previously believed there were only 150 of them left.
The charity is looking (for/of) 20 volunteers for a project next January. You have to pay (on/for) your flights and also £500 for a two - week project. They spend the money (on/with) school and clean water - Madagascar isn't a rich country Accommodation and meals are free.

6 лет назад

Предмет: Химия, автор: lRital

Обьясните, как вычислять уравнения реакций. Например, C2H4 + H2 → ?
Просто нам такое на уроках задают, а я не знаю, что отвечать. Ответ будет C2H6, но мне бы хотелось узнать, как именно получить этот ответ.

10 лет назад

Предмет: Математика, автор: pamelavolonkov

1.Один угол треугольника втрое больше,чем второй,и на 30 градусовы больше третьего угла.Определите углы треугольника.Какой это треугольник.

2.Разложить на множители числа 210 и 180

10 лет назад