The set of values of $x$ for which $f(x)=3x^4-8x^3-6x^2+24x-12$ is an increasing function,is

The function $\sin x - \cos x$ is increasing in the interval

Let $f$ be any function continuous on $[a, b]$ and twice differentiable on $(a, b)$. If for all $x \in (a, b)$,$f^{\prime}(x) > 0$ and $f^{\prime \prime}(x) < 0$,then for any $c \in (a, b)$,$\frac{f(c)-f(a)}{f(b)-f(c)}$ is greater than

If $5 f(x)+4 f\left(\frac{1}{x}\right)=x^2-2, \forall x \neq 0$ and $y=9 x^2 f(x)$,then $y$ is strictly increasing in :

Let $p(x)$ be a polynomial with real coefficients, $p(0) = 1$ and $p^{\prime}(x) > 0$ for all $x \in \mathbb{R}$. Then

If $f(x)=x^3+b x^2+c x+d$ and $0 < b^2 < c$,then in $(-\infty, \infty)$