In the evenings into the city and go clubbing or see a movie. a lot of new friends. my pronunciation is much better already, and almost everything. On weekdays Liam. At the moment on their new website and help with it. some useful stuff about how people business in this country.
to see me? the winter holiday skiing with Ryan and Liam. to meet you and there’s plenty of space. You must bring lots of warm clothes because really cold here in the winter. Let me know as soon as . And tell me what these days.
Скорость первого катера:
v₁ = 60/t
Скорость второго катера:
v₂ = 60/(t+1)
Скорость сближения катеров:
v = v₁+v₂ = 60/t + 60/(t+1) =
= 60(t+1)+60t)/(t(t+1)) = (120t+60)/(t²+t)
По условию: v = S/t' = 50:1 = 50 (км/ч)
Тогда:
120t + 60 = 50t² + 50t
50t² - 70t - 60 = 0
5t² - 7t - 6 = 0 D = b²-4ac = 49+120 = 169
t₁ = (-b+√D)/2a = 2 (ч)
t₂ = (-b-√D)/2a = -0,6 (ч) - не удовлетворяет условию
Тогда скорость первого катера:
v₁ = 60/t = 60:2 = 30 (км/ч)
Скорость второго катера:
v₂ = 60/(t+1) = 60:3 = 20 (км/ч)
ответ: 30 км/ч; 20 км/ч.
Объяснение:
f(x) = 3(x)^-2 - x
F(x) = -3/x - x²/2 + С