let give I(x)= ∫_0 ^(π/2) (dt/(√(sin^2 t +x^2 cos^2 t))) and
J(x)= ∫_0 ^(π/2) ((cost)/(√(sin^2 t +x^2 cos^2 t)))dt cslculate lim_(x→0^+ ) (I(x)−J(x))
and prove that I(x)=_(x→0^+ ) −lnx +2ln2 +o(1).
let give B(x,y)= ∫_0 ^1 u^(x−1) (1−u)^(y−1) du and (beta function)
and Γ(x) =∫_0 ^∞ u^(x−1) e^(−u) du (x>0)(gamma function of euler)
1) prove that Γ(x)= 2∫_0 ^∞ u^(2x−1) e^(−u^2 ) du .
2) prove that B(x,y) = ((Γ(x).Γ(y))/(Γ(x+y))) .