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

Задание

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

\(\displaystyle \small x\)\(\displaystyle \small -3\)\(\displaystyle \small -2\)\(\displaystyle \small -1\)
\(\displaystyle \small y=2|x|\)

 

\(\displaystyle \small x\)\(\displaystyle \small 0\)\(\displaystyle \small 1\)\(\displaystyle \small 2\)\(\displaystyle \small 3\)
\(\displaystyle \small y=2|x|\)


Постройте график по полученным точкам:
 

Решение

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

\(\displaystyle x\)\(\displaystyle \small -3\)\(\displaystyle \small -2\)\(\displaystyle \small -1\)
\(\displaystyle y=2|x|\)\(\displaystyle \small 2|-3|\)\(\displaystyle \small 2|-2|\)\(\displaystyle \small 2|-1|\)

 

\(\displaystyle x\)\(\displaystyle \small 0\)\(\displaystyle \small 1\)\(\displaystyle \small 2\)\(\displaystyle \small 3\)
\(\displaystyle y=2|x|\)\(\displaystyle \small 2|0|\)\(\displaystyle \small 2|1|\)\(\displaystyle \small 2|2|\)\(\displaystyle \small 2|3|\)


Вычислим значения:

\(\displaystyle x\)\(\displaystyle \small -3\)\(\displaystyle \small -2\)\(\displaystyle \small -1\)
\(\displaystyle y=2|x|\)\(\displaystyle \small 6\)\(\displaystyle \small 4\)\(\displaystyle \small 2\)

 

\(\displaystyle x\)\(\displaystyle \small 0\)\(\displaystyle \small 1\)\(\displaystyle \small 2\)\(\displaystyle \small 3\)
\(\displaystyle y=2|x|\)\(\displaystyle \small 0\)\(\displaystyle \small 2\)\(\displaystyle \small 4\)\(\displaystyle \small 6\)


Построим точки на плоскости и соединим их линией:


Получили график функции \(\displaystyle y=2|x|\) на отрезке \(\displaystyle [-3;3]{\small .}\)