∫dx(a2+x2)32 =
x(a2+x2)32+c
xa2(a2+x2)32+c
1a2(a2+x2)32+c
None of these
Put x=a tanθ ⇒dx=asec2θ dθ∴I=∫asec2θa2+a2tan2θ32dθ =∫asec2θa3sec2θ32dθ =1a2∫dθsecθ =1a2∫cosθ dθ =1a2sinθ+c =xa2a2+x232+c