∴當(dāng)-2≤a≤2時(shí),g(a)=f(a)=a2-1;
當(dāng)a<-2時(shí),g(a)=f(-2)=-4a-5;
當(dāng)a>2時(shí),g(a)=f(2)=4a-5;
∴g(a)=
|
∴當(dāng)-2≤a≤2時(shí),g(a)=a2-1,∴-1≤g(a)<3;
當(dāng)a>2時(shí),g(a)=4a-5,∴g(a)>3;
當(dāng)a<-2時(shí),g(a)=-4a-5,∴g(a)>3;
綜上所得:g(a)≥-1,
故g(a)的最小值為-1,此時(shí)a=0.