Question

Найдите множество значений функции y=2[sinx]-1.................sinx по модулю

Answer 1

$-1 \leq sin(x) \leq 1\\\\ 0 \leq |sin(x)| \leq 1\\\\ 2*0 \leq 2*|sin(x)| \leq 2*1\\\\ 0 \leq 2*|sin(x)| \leq 2\\\\ 0-1 \leq 2*|sin(x)|-1 \leq 2-1\\\\ -1 \leq 2*|sin(x)|-1 \leq 1\\\\ -1 \leq y(x) \leq 1\\\\ y\in[-1;\ 1]$