Beta Function Calculator

B(a,b) = Γ(a)Γ(b)/Γ(a+b)

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About Beta Function Calculator

A Beta function calculator computing B(a,b) = ∫₀¹ tᵃ⁻¹(1−t)ᵇ⁻¹dt = Γ(a)Γ(b)/Γ(a+b). Shows Gamma function values, relationship to binomial coefficients, and the incomplete Beta function. Essential for Beta distributions. All calculations are client-side.

Beta Function Calculator Features

  • B(a,b)
  • Γ values
  • Symmetry
  • Integer cases
  • Properties
Beta function: B(a,b) = ∫₀¹ tᵃ⁻¹(1−t)ᵇ⁻¹dt = Γ(a)Γ(b)/Γ(a+b). Symmetric: B(a,b) = B(b,a). For integers: B(m,n) = (m−1)!(n−1)!/(m+n−1)! = 1/[n·C(m+n−1,m−1)]. Beta distribution: f(x) = xᵃ⁻¹(1−x)ᵇ⁻¹/B(a,b).

How to Use

Enter parameters:

  • a, b: Positive real numbers
  • B(a,b): Beta function value
  • Related: Gamma function values

Properties

  • B(a,b) = B(b,a)
  • B(a,b) = 2∫₀^(π/2) sin²ᵃ⁻¹θ cos²ᵇ⁻¹θ dθ
  • B(a,1) = 1/a
  • B(1/2,1/2) = π

Applications

  • Beta distribution in Bayesian statistics
  • Binomial coefficient generalization
  • Wallis integrals
  • String theory amplitudes

Step-by-Step Instructions

  1. 1Enter a and b.
  2. 2Get B(a,b).
  3. 3View Γ(a), Γ(b).
  4. 4Check symmetry.
  5. 5See properties.

Beta Function Calculator — Frequently Asked Questions

How is Beta related to Gamma?+

B(a,b) = Γ(a)Γ(b)/Γ(a+b). This is the fundamental connection. For positive integers: B(m,n) = (m−1)!(n−1)!/(m+n−1)!. The Beta function is essentially a normalized product of Gamma functions.

Why is B(1/2,1/2) = π?+

B(1/2,1/2) = Γ(1/2)²/Γ(1) = (√π)²/1 = π. Alternatively, B(1/2,1/2) = 2∫₀^(π/2) dθ = π. This connects the Beta function to circular geometry through the Gamma function at half-integers.

What is the incomplete Beta function?+

Bₓ(a,b) = ∫₀ˣ tᵃ⁻¹(1−t)ᵇ⁻¹dt. The regularized version Iₓ(a,b) = Bₓ(a,b)/B(a,b) is the CDF of the Beta distribution. Used for computing binomial probabilities and F-distribution values.

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