Question

Найдите значения x, при которых(на фото)

Answer 1

$f(x)=5x-x^3\\f'(x)=5-3x^2 geq 0\\3x^2-5 leq 0\\(sqrt3x-sqrt5)(sqrt3x+sqrt5) leq 0\\+ + + + [-sqrt{frac{5}{3}}]- -- - - - [sqrt{frac{5}{3}}]+ + + + + \\xin [-sqrt{frac{5}{3}},sqrt{frac{5}{3}}]$