Find the (absolute) maximum and the (absolute) minimum values of the following functions in the indicated intervals. Also find the points of (absolute) maxima and minima:

$f\left(x\right)=\sin x+\cos x$ in $\left[0,\mathrm{\pi }\right]$.

Find the (absolute) maximum and the (absolute) minimum values of the following functions in the indicated intervals. Also find the points of (absolute) maxima and minima:

$f\left(x\right)=3+\left|x+1\right|$ in $\left[-2,3\right]$

Find the turning points of the following functions and distinguish between them. Also find the local maximum and minimum values of the functions : 

$f\left(x\right)=2x^3-21x^2+36x-20$

Find the turning points of the following functions and distinguish between them. Also find the local maximum and minimum values of the functions : 

$f\left(x\right)=4x^3+19x^2-14x+3$

Find the turning points of the following functions and distinguish between them. Also find the local maximum and minimum values of the functions : 

$f\left(x\right)=x^3-3x^2+3x$

Find the coordinates of stationary points on the curve

$y=x^3-3x^2-9x+7$