Задача 32285 ...

rita456737

2018-12-22 10:55:53

Найдите [m] f \left( \frac{\pi}{9} \right) [/m], если [m] f(x) = - \frac{1}{3} \text{tg} \ 3x [/m]

Выберите ответ:

○ - [m]\frac{1}{2}[/m]

○ -4

○ 2

○ [m]\frac{1}{4}[/m]

○ - [m]\frac{1}{4}[/m]

sova

2018-12-22 11:00:57

★

f `(x)=(-1/3)*(tg3x)`=(-1/3)*(1/cos^23x)*(3x)`=-1/cos^23x
f`(π/9)=-1/cos^2(π/3)=-4