Такая функция называется параболой, что и отражено в последнем вопросе. Ветви располагаются в зависимости от знака параметра а: если а - положительный, то ветви направлены вверх, если отрицательный - вниз. Область определения - от минус бесконечности до плюс бесконечности, т.к. возведение в квадрат не накладывает на аргумент никаких ограничений. Область значений от нуля до плюс бесконечности, т.к. квадрат числа не может быть отрицательным.
В общем виде уравнение параболы записывается так: y = a*x^2 + b*x + c Тогда вершина находится так: x0 = -b/(2*a) y0 = (4*a*c - b^2)/(4*a)
В приведенном случае b = 0, с = 0, т.о. вершина лежит в точке (0, 0)
My Day My every day activities are quite routine. They do not differ much from those of any other pupil of our country. My working day begins at 7 o’clock in the morning when I get up. I do my physical jerks, wash, brush my teeth and comb my hair. Then I have breakfast. For breakfast I usually have toasted bread, fried eggs, corn flakes, tea or coffee and some jam. At ten to eight I leave for school. I go to school five days a week. It takes me twenty minutes to get to school by bus. At school I usually have six or seven lessons. The lessons are over at two o’clock. I return home at three o’clock. I have lunch and take a short rest.I go for a walk with my friends. In spring we play football, in winter we play hockey or ski. I am back at home at a quarter past four. At four thirty I begin to do my home-work. It takes me three hours to do it. On Monday, Wednesday and Friday I attend preparatory courses at the University. I leave home, at four thirty and come back at eight thirty. My parents usually return home at seven o’clock. When I am at home we have dinner at seven thirty. After dinner we go to the sitting-room. There we read books, watch TV, chat with the friends on the phone. At ten o’clock I take a shower, brush my teeth and go to bed. I fall asleep fast and have no dreams.
В общем виде уравнение параболы записывается так:
y = a*x^2 + b*x + c
Тогда вершина находится так:
x0 = -b/(2*a)
y0 = (4*a*c - b^2)/(4*a)
В приведенном случае b = 0, с = 0, т.о. вершина лежит в точке (0, 0)