If $\mathrm{f}(1)=1, \mathrm{f}^{\prime}(1)=3$, then the derivative of $\mathrm{f}(\mathrm{f}(\mathrm{f}(x)))+(\mathrm{f}(x))^2$ at $x=1$ is

If $\theta$ denotes the acute angle between the curves $y=10-x^2$ and $y=2+x^2$, at a point of the intersection, then $|\tan \theta|$ is equal to

If $y=a \log x+b x^2+x$ has its extremum values at $x=-1$ and $x=2$, then

The set of all points, for which $f(x)=x^2 e^{-x}$ strictly increases, is