If limx→0asinx−bx+cx2+x32x2log(1+x)−2x3+x4 exists and is finite, then
a=b
c=0
a=6
limx→0a(x−x36+x5120−.....)−bx+cx2+x32x2(x−x22+x33−......)−2x3+x4
=limx→0(a−b)x+cx2+(1−a6)x3+ax5120+....2x53−x62+....
For this limit to exist we must have a−b=0,c=0, and 1−a6=0, that is, a=b=6 and c=0