Question

Найдите множество значений функции
f(x)=3cos5x-4

Answer 1

$f(x)=3cos5x-4\\\\-1\leq cos5x\leq 1\\\\-3\leq 3cos5x\leq 3\\\\-7\leq cos5x-4\leq -1\\\\f(x)\in [-7,-1\, ]$