Question

Помогите, пожалуйста

Answer 1

Ответ:

Объяснение:

y = 9cosx + 12sinx + 6

$\displaystyle\\\bf9cosx+12sinx=15\cdot\bigg(\frac{3}{5}cosx+\frac{4}{5} sinx\bigg)\\\\\bigg(\frac{3}{5} \bigg)^2+\bigg(\frac{4}{5} \bigg)^2=1\\\\cos^2\alpha +sin^2\alpha =1\\\\\frac{3}{5} =cos\alpha ;\ \ \ \ \frac{4}{5}=sin\alpha\\\\\\9cosx+12sinx=15\cdot(cos\alpha *cosx+sin\alpha *sinx)=15cos(\alpha -x)\\\\\\-1\leq cos(\alpha -x)\leq 1\\\\-15\leq 15cos(\alpha -x)\leq 15\\\\-15\leq 9cosx+12sinx\leq 15\\\\-15+6 \leq 9cosx+12sinx+6\leq 15+6\\\\-9\leq 9cosx+12sinx+6\leq 21$