We have,
limx→0[xsin2x\alphaxex−βloge(1+x)+γx2e−x]=10
⇒limx→0x3(x2sin2x)\alphax(1+x+2!x2+..)−β(x−2x2+3x3−...)+γx2(1−x+2!x2−..)=10
⇒limx→0x3\alphax(1+x+2x2)−β(x−2x2+3x3)+γx2(1−x)=10
Neglecting higher powers.
limx→0x3x(α−β)+x2(α+2β+γ)+x3(2α−3β−γ)=10
For limit to exist
α−β=0
α+2β+γ=0
2α−3β−γ=10…(i)
β=α,γ=−23α
Putting in \left(i\right),weget</p><p>\dfrac{\alpha}{2} - \dfrac{\alpha}{3} + \dfrac{3\alpha}{2} = 10</p><p>⇒ \dfrac{\alpha}{6} + \dfrac{3\alpha}{2} = 10</p><p>⇒ \dfrac{\alpha + 9\alpha}{6} = 10</p><p>⇒ \alpha = 6</p><p>Hence,</p><p>\alpha = 6, \beta = 6, \gamma = - 9</p><p>⇒ \alpha + \beta + \gamma = 3