limx→0xasinb xsin(xc),a,b,b ∈ R ~ {0} exists and has non-zero value, then
a, b, c are in AP
a, b, c are in GP
a, b, c are in HP
a+b=c
= limx→0xa+b−c(sin xx)b(sin(xc)xc)
The above limit has non-zero value only when