Calculate Gamma Function

Online calculator and formulas for calculating the Euler Gamma function

Gamma Function Calculator

Using the Calculator

Enter the argument x and click 'Calculate'. For integers ≤ 0 the result is ±∞.

Real number > 0 for the Gamma function
Result
Γ(x):

Gamma Function Curve

Mouse pointer on the graph shows the values.
Y-scale is limited to ±20 for better visualization.

Euler Gamma Function Formulas

Integral Representation
\[\Gamma(x) = \int_0^{\infty} t^{x-1} e^{-t} dt\]

for Re(x) > 0

Factorial Relationship
\[\Gamma(n+1) = n!\]

for natural numbers n

Recurrence Formula
\[\Gamma(x+1) = x \cdot \Gamma(x)\]
Reflection Formula
\[\Gamma(x)\Gamma(1-x) = \frac{\pi}{\sin(\pi x)}\]

Special Values

Important Values
Γ(1) = 1 Γ(2) = 1 Γ(3) = 2 Γ(4) = 6 Γ(5) = 24
Half-Integer Values
\[\Gamma\left(\frac{1}{2}\right) = \sqrt{\pi}\]

≈ 1.772453851

Example

Γ(0.5) = √π ≈ 1.772
Γ(1.5) = 0.5 × √π ≈ 0.886
Γ(2.5) = 1.5 × 0.5 × √π ≈ 1.329

Comprehensive Description of the Gamma Function

Mathematical Definition

The Euler Gamma function is one of the most important special functions in mathematics. It extends the factorial function to real and complex numbers and is denoted by the Greek symbol Γ (Gamma).

Euler Gamma Function

The Γ(x) function is one of the most important special functions in analysis and function theory. It generalizes the factorial to real numbers.

Historical Background

The Gamma function was introduced by Leonhard Euler in the 18th century and later developed further by Adrien-Marie Legendre and Carl Friedrich Gauss. It plays a central role in many areas of mathematics.

Properties and Applications

Mathematical Applications
  • Probability theory (Beta distribution, Gamma distribution)
  • Combinatorics (generalization of factorial)
  • Analytic number theory (Riemann zeta function)
  • Differential equations and integral calculus
Physical Applications
  • Quantum mechanics (hydrogen atom, harmonic oscillator)
  • Statistical mechanics (Maxwell-Boltzmann distribution)
  • Nuclear physics (radioactive decay)
  • Astrophysics (stellar evolution)
Special Properties
  • Holomorphic: Γ(z) is holomorphic except at z = 0, -1, -2, ...
  • Functional equation: Γ(z+1) = z·Γ(z)
  • Convexity: log Γ(x) is convex for x > 0
  • Stirling's formula: Asymptotic expansion for large x
Interesting Facts
  • Γ(x) has poles at x = 0, -1, -2, -3, ...
  • The Bohr-Mollerup theorem characterizes Γ uniquely
  • Connection to Beta function: B(x,y) = Γ(x)Γ(y)/Γ(x+y)
  • The Gamma function is the unique log-convex extension of the factorial

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