Предмет: Геометрия, автор: viktoriiaki738

Знайдіть модуль вектора с = -6а(вектор)- 7b(вектор), якщо a(-1; 1; 1) i b(2; 2; -2).

Ответы

Автор ответа: flsh

Ответ:

$|\vec c| =4\sqrt{33}$

Объяснение:

$\vec c=-6\vec a-7\vec b$ = -6·(-1; 1; 1) - 7·(2; 2; -2) = (6; -6; -6) + (-14; -14; 14) = (-8; -20; 8)

$|\vec c| = \sqrt{(-8)^2+(-20)^2+8^2}= \sqrt{64+400+64}= \sqrt{128+400}= \sqrt{528}=\sqrt{16\cdot33}=\sqrt{16}\cdot\sqrt{33}=4\sqrt{33}$

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