Let g(x)=x2+xtan⁡x−xtan⁡2xax+tan⁡x−tan⁡3x,x≠00,x=0 If g1(0) exists and is equal to non-zero value b then b is equal to

g10=b=Ltx→0 x2+xtanx−xtan2xxax+tanx−tan3x=Ltx→0 x+tanx−tan2xax+tanx−tan3x=Ltx→0  xx+x33+215x5+-------∞−2x+8x33+-----∞axx+x33+215x5+-------∞−3x+27x33+-----∞ On simplifying a=2__,b=726