If $f(x)=x^x$, then the interval in which $f(x)$ decrease is

If the Rolle's theorem is applicable for the function $f(x)$ defined by $f(x)=x^3+P x-12$ on $[0,1]$ then the value of $C$ of the Rolle's theorem is

The number of all the value of $x$ for which the function $f(x)=\sin x+\frac{1-\tan ^2 x}{1+\tan ^2 x}$ attains it maximum value on [ $0.2 \pi$ ] is

Equation of a tagent line of the parabola $y^2=8 x$, which passes through the point $(1,3)$ is