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📐 Mathematics  ·  Integrals  ·  JEE

The Beta function B(m,n) = integral from 0 to 1 of x<sup>m-1</sup>(1-x)<sup>n-1</sup> dx is related to Gamma by:

Answer: B(m,n) = Gamma(m)Gamma(n)/Gamma(m+n).

  • A B(m,n) = Gamma(m+n)/[Gamma(m)Gamma(n)]
  • B B(m,n) = Gamma(m)Gamma(n)/Gamma(m+n)
  • C B(m,n) = Gamma(m) + Gamma(n)
  • D B(m,n) = m! × n!/(m+n)!

Correct answer: B. B(m,n) = Gamma(m)Gamma(n)/Gamma(m+n)

Explanation: Using the Gamma convolution: Γ(m)Γ(n) = ∫₀^∞ u<sup>m−1</sup>e<sup>−u</sup>du · ∫₀^∞ v<sup>n−1</sup>e<sup>−v</sup>dv. Substituting u=t·s, v=t(1−s) and integrating out t gives B(m,n) = Γ(m)Γ(n)/Γ(m+n).

xyabArea = integral of f(x) dxRectangles approximate the area (Riemann sum)

The exact area under the curve from a to b (shaded) is approximated by a few rectangles, the Riemann sum idea behind the definite integral.

Concept context

Indefinite and definite integrals, areas under curves

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