Given f(x)={\begin{matrix}{x}^{2}-4x-2, & \forall x\in (-1,\frac{3-\sqrt{17}}{2}) \\ -{x}^{2}+2x+2, & \forall x\in [\frac{3-\sqrt{17}}{2},2)\end{matrix}
When x∈(−1,23−17)
f′(x)=2x−4=0⇒x=2
Now f(2)=2, f(−1)=3
f(23−17)=217−3
When x∈[23−17,2)
f′(x)=−2x+2
f′(x)=−2(x−1)
f′(x)=0 when x=1
f(1)=3
Hece, absolute minimum value =217−3
and absolute maximum value =3
Sum =217−3+3=217+3