The integral 16∫12dxx3(x2+2)2 is equal to [2023]
(1)
Let I=16∫12dxx3(x2+2)2=16∫121x7(1+2x2)2dx
Let 1+2x2=p ⇒ -4x3dx=dp ⇒ dxx3=-14dp
I=-4∫33/2dp4(p-1)2·p2
=-4∫33/2(p-1)2dp4p2 =-∫33/2p2+1-2pp2dp
=-∫33/2(1+1p2-2p)dp=-[p-1p-2logp]33/2
=-[{56-2loge(32)}-{83-2loge3}]
=-[2loge2-116]=116-loge22=116-loge4