Найди экстремумы и схематически изобрази график функции y=10x^2e^x. Запиши значения точек экстремума (при необходимости результат округли до десятых (e=2,7). Укажи промежутки возрастания
Раз по реке она шла меньше времени при большем расстоянии, значит явно шла по течению. Пусть её собственная скорость V, время пути по реке t, тогда верны следующие соотношения(не забудем перевести минуты в часы): 36 = (V+2)*t, 35 = V * (t+1/20) Раскрываем скобки: 36 = Vt+2t 35=Vt+V/20 Вычитаем из второго уравнения первое: 1 = V/20 - 2t Выражаем скорость: V/20 = 1 + 2t V = 20 + 40 t Подставим это соотношение, например, в первое уравнение: 36=(20+40t+2)t 36 = 40 t^2 + 22 t 40 t^2 + 22 t - 36 = 0 Сокращаем: 20 t ^2 + 11 t - 18 = 0 Решаем квадратное уравнение: D = 11*11 + 4 *20*18 = 121 + 1440 = 1561 = 39,5 (округлённо) t = (-11+-(39,5)) / 40 = {-1,25; 0,7} Время отрицательным быть не может, единственный подходящий результат - 0,7 ч. Подставляем в полученное выражение скорости: V = 20 + 40 t = 20 + 40 * 0,7 = 48 км/ч. Хотя явно не очень сходится, даже со всеми округлениями. Возможно, в вычислениях ошибся, но ход решения примерно такой.
WRITING Choose ONE of the topics and write. Topic 1: You are a charitable volunteer in your city and always give a hand to those who are in need: clean the apartments of the disabled people; bring food to animal refuges to feed homeless animals; organise campaigns to raise money and collect toys and clothes for the local orphanages. Your new idea is to write a formal letter to the local mayor to ask him/her for any help he/she can provide to help your charity organisation. Include in your letter the following information: • The title of your charity organisation: • What you have done/are doing aiready; • How you would like the mayor to help your charity organisation. Use appropriate style and examples in your letter.WRITING Choose ONE of the topics and write. Topic 1: You are a charitable volunteer in your city and always give a hand to those who are in need: clean the apartments of the disabled people; bring food to animal refuges to feed homeless animals; organise campaigns to raise money and collect toys and clothes for the local orphanages. Your new idea is to write a formal letter to the local mayor to ask him/her for any help he/she can provide to help your charity organisation. Include in your letter the following information: • The title of your charity organisation: • What you have done/are doing aiready; • How you would like the mayor to help your charity organisation. Use appropriate style and examples in your letter.WRITING Choose ONE of the topics and write. Topic 1: You are a charitable volunteer in your city and always give a hand to those who are in need: clean the apartments of the disabled people; bring food to animal refuges to feed homeless animals; organise campaigns to raise money and collect toys and clothes for the local orphanages. Your new idea is to write a formal letter to the local mayor to ask him/her for any help he/she can provide to help your charity organisation. Include in your letter the following information: • The title of your charity organisation: • What you have done/are doing aiready; • How you would like the mayor to help your charity organisation. Use appropriate style and examples in your letter.WRITING Choose ONE of the topics and write. Topic 1: You are a charitable volunteer in your city and always give a hand to those who are in need: clean the apartments of the disabled people; bring food to animal refuges to feed homeless animals; organise campaigns to raise money and collect toys and clothes for the local orphanages. Your new idea is to write a formal letter to the local mayor to ask him/her for any help he/she can provide to help your charity organisation. Include in your letter the following information: • The title of your charity organisation: • What you have done/are doing aiready; • How you would like the mayor to help your charity organisation. Use appropriate style and examples in your letter.WRITING Choose ONE of the topics and write. Topic 1: You are a charitable volunteer in your city and always give a hand to those who are in need: clean the apartments of the disabled people; bring food to animal refuges to feed homeless animals; organise campaigns to raise money and collect toys and clothes for the local orphanages. Your new idea is to write a formal letter to the local mayor to ask him/her for any help he/she can provide to help your charity organisation. Include in your letter the following information: • The title of your charity organisation: • What you have done/are doing aiready; • How you would like the mayor to help your charity organisation. Use appropriate style and examples in your letter.
36 = (V+2)*t,
35 = V * (t+1/20)
Раскрываем скобки:
36 = Vt+2t
35=Vt+V/20
Вычитаем из второго уравнения первое:
1 = V/20 - 2t
Выражаем скорость:
V/20 = 1 + 2t
V = 20 + 40 t
Подставим это соотношение, например, в первое уравнение:
36=(20+40t+2)t
36 = 40 t^2 + 22 t
40 t^2 + 22 t - 36 = 0
Сокращаем:
20 t ^2 + 11 t - 18 = 0
Решаем квадратное уравнение:
D = 11*11 + 4 *20*18 = 121 + 1440 = 1561 = 39,5 (округлённо)
t = (-11+-(39,5)) / 40 = {-1,25; 0,7}
Время отрицательным быть не может, единственный подходящий результат - 0,7 ч. Подставляем в полученное выражение скорости:
V = 20 + 40 t = 20 + 40 * 0,7 = 48 км/ч.
Хотя явно не очень сходится, даже со всеми округлениями. Возможно, в вычислениях ошибся, но ход решения примерно такой.
Объяснение:
WRITING Choose ONE of the topics and write. Topic 1: You are a charitable volunteer in your city and always give a hand to those who are in need: clean the apartments of the disabled people; bring food to animal refuges to feed homeless animals; organise campaigns to raise money and collect toys and clothes for the local orphanages. Your new idea is to write a formal letter to the local mayor to ask him/her for any help he/she can provide to help your charity organisation. Include in your letter the following information: • The title of your charity organisation: • What you have done/are doing aiready; • How you would like the mayor to help your charity organisation. Use appropriate style and examples in your letter.WRITING Choose ONE of the topics and write. Topic 1: You are a charitable volunteer in your city and always give a hand to those who are in need: clean the apartments of the disabled people; bring food to animal refuges to feed homeless animals; organise campaigns to raise money and collect toys and clothes for the local orphanages. Your new idea is to write a formal letter to the local mayor to ask him/her for any help he/she can provide to help your charity organisation. Include in your letter the following information: • The title of your charity organisation: • What you have done/are doing aiready; • How you would like the mayor to help your charity organisation. Use appropriate style and examples in your letter.WRITING Choose ONE of the topics and write. Topic 1: You are a charitable volunteer in your city and always give a hand to those who are in need: clean the apartments of the disabled people; bring food to animal refuges to feed homeless animals; organise campaigns to raise money and collect toys and clothes for the local orphanages. Your new idea is to write a formal letter to the local mayor to ask him/her for any help he/she can provide to help your charity organisation. Include in your letter the following information: • The title of your charity organisation: • What you have done/are doing aiready; • How you would like the mayor to help your charity organisation. Use appropriate style and examples in your letter.WRITING Choose ONE of the topics and write. Topic 1: You are a charitable volunteer in your city and always give a hand to those who are in need: clean the apartments of the disabled people; bring food to animal refuges to feed homeless animals; organise campaigns to raise money and collect toys and clothes for the local orphanages. Your new idea is to write a formal letter to the local mayor to ask him/her for any help he/she can provide to help your charity organisation. Include in your letter the following information: • The title of your charity organisation: • What you have done/are doing aiready; • How you would like the mayor to help your charity organisation. Use appropriate style and examples in your letter.WRITING Choose ONE of the topics and write. Topic 1: You are a charitable volunteer in your city and always give a hand to those who are in need: clean the apartments of the disabled people; bring food to animal refuges to feed homeless animals; organise campaigns to raise money and collect toys and clothes for the local orphanages. Your new idea is to write a formal letter to the local mayor to ask him/her for any help he/she can provide to help your charity organisation. Include in your letter the following information: • The title of your charity organisation: • What you have done/are doing aiready; • How you would like the mayor to help your charity organisation. Use appropriate style and examples in your letter.