Question

Решите неравенство ...................

Answer 1

Ответ:

$f(x)=x^3-14x\\\\f'(x)=3x^2-14\ \ ,\\\\3x^2-14<0\ \ ,\ \ x^2-\dfrac{14}{3}<0\ \ ,\\\\\Big(x-\sqrt{\dfrac{14}{3}}\Big)\Big(x+\sqrt{\dfrac{14}{3}}\Big)<0\\\\\\x\in \Big(-\sqrt{\dfrac{14}{3}}\ ;\ \sqrt{\dfrac{14}{3}}\Big)$