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Теория: 15 Построение графика функции, содержащей модуль, по точкам

Задание

Заполните таблицу значений функции \(\displaystyle y=-2|x-2|{\small .}\)

\(\displaystyle \small x\)\(\displaystyle \small -1\)\(\displaystyle \small 0\)\(\displaystyle \small 1\)
\(\displaystyle \small y=-2|x-2|\)

 

\(\displaystyle \small x\)\(\displaystyle \small 2\)\(\displaystyle \small 3\)\(\displaystyle \small 4\)\(\displaystyle \small 5\)
\(\displaystyle \small y=-2|x-2|\)


Постройте график по полученным точкам:
 

Решение

Заполним таблицу значений функции \(\displaystyle y=-2|x-2|{\small :}\)

\(\displaystyle x\)\(\displaystyle \small -1\)\(\displaystyle \small 0\)\(\displaystyle \small 1\)
\(\displaystyle y=-2|x-2|\)\(\displaystyle \small -2|-1-2|\)\(\displaystyle \small -2|0-2|\)\(\displaystyle \small -2|1-2|\)

 

\(\displaystyle x\)\(\displaystyle \small 2\)\(\displaystyle \small 3\)\(\displaystyle \small 4\)\(\displaystyle \small 5\)
\(\displaystyle y=-2|x-2|\)\(\displaystyle \small -2|2-2|\)\(\displaystyle \small -2|3-2|\)\(\displaystyle \small -2|4-2|\)\(\displaystyle \small -2|5-2|\)


Вычислим значения:

\(\displaystyle x\)\(\displaystyle \small -1\)\(\displaystyle \small 0\)\(\displaystyle \small 1\)
\(\displaystyle y=-2|x-2|\)\(\displaystyle \small -6\)\(\displaystyle \small -4\)\(\displaystyle \small -2\)

 

\(\displaystyle x\)\(\displaystyle \small 2\)\(\displaystyle \small 3\)\(\displaystyle \small 4\)\(\displaystyle \small 5\)
\(\displaystyle y=-2|x-2|\)\(\displaystyle \small 0\)\(\displaystyle \small -2\)\(\displaystyle \small -4\)\(\displaystyle \small -6\)


Построим точки на плоскости и соединим их линией:


Получили график функции \(\displaystyle y=-2|x-2|\) на отрезке \(\displaystyle [-1;5]{\small .}\)