If limx→af(x)g(x) exists, then
both limx→af(x) and limx→ag(x) must exist
both limx→af(x) need not exist but limx→ag(x) exists
neither limx→af(x) nor limx→ag(x) may exist
limx→af(x) exists but limx→ag(x) need not exist
If fx=sin1x and gx=1x, then both limx→0 fx and limx→0 gx do not exist, but limx→0 fxgx =0 exists.