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

Задание

Заполните таблицу значений функции \(\displaystyle y=-3|x|{\small .}\)

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

 

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


Постройте график по полученным точкам:
 

Решение

Заполним таблицу значений функции \(\displaystyle y=-3|x|{\small :}\)

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

 

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


Вычислим значения:

\(\displaystyle x\)\(\displaystyle \small -3\)\(\displaystyle \small -2\)\(\displaystyle \small -1\)
\(\displaystyle y=-3|x|\)\(\displaystyle \small -9\)\(\displaystyle \small -6\)\(\displaystyle \small -3\)

 

\(\displaystyle x\)\(\displaystyle \small 0\)\(\displaystyle \small 1\)\(\displaystyle \small 2\)\(\displaystyle \small 3\)
\(\displaystyle y=-3|x|\)\(\displaystyle \small 0\)\(\displaystyle \small -3\)\(\displaystyle \small -6\)\(\displaystyle \small -9\)


Построим точки на плоскости и соединим их линией:


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