# GAMMALN

The `GAMMALN` function returns the natural logarithm of the absolute value of the Gamma function, Γ(x). The Gamma function is defined as an extension of the factorial function to complex and real numbers. The function is commonly used in probability theory and statistics to compute probabilities and to model continuous distributions such as the chi-squared and F distributions.

## Usage

Use the `GAMMALN` formula with the syntax shown below, it has 1 required parameter:

Parameters:
1. value (required):
The value for which to compute the natural logarithm of the absolute value of the Gamma function. Value must be positive and cannot be 0.

## Examples

Here are a few example use cases that explain how to use the `GAMMALN` formula in Google Sheets.

### Compute probabilities for the chi-squared distribution

The chi-squared distribution is used to model the sum of squared random variables. The `GAMMALN` function can be used to compute probabilities for this distribution by first computing the natural logarithm of the Gamma function and then using it in the probability density function.

### Compute probabilities for the F distribution

The F distribution is used to model the ratio of variances of two populations. The `GAMMALN` function can be used to compute probabilities for this distribution by first computing the natural logarithm of the Gamma function and then using it in the probability density function.

### Compute the logarithm of large factorials

The Gamma function is an extension of the factorial function to real and complex numbers. The `GAMMALN` function can be used to compute the natural logarithm of large factorials by first computing the natural logarithm of the Gamma function and then applying Stirling's approximation.

## Common Mistakes

`GAMMALN` not working? Here are some common mistakes people make when using the `GAMMALN` Google Sheets Formula:

### Not providing a value

This will return an error if the value is not provided as it is a required argument.

### Providing a non-numeric value

This will return an error if the value provided is not a number.

### Using a negative value

This will return an error if the value provided is negative.

The following functions are similar to `GAMMALN` or are often used with it in a formula:

• `GAMMA`

The GAMMA function returns the Gamma function evaluated at the input value. The Gamma function is a commonly used function in mathematics, and is used in many statistical calculations. It is defined as the integral of t^(x-1)*e^(-t) from 0 to infinity. The GAMMA function can be used to calculate probabilities of certain events in statistical distributions.

• `LN`

The `LN` formula returns the natural logarithm of a given value. The natural logarithm is the logarithm to the base e, where e is an irrational number approximately equal to 2.71828. The formula is commonly used in mathematical and scientific calculations.

• `EXP`

The `EXP` function returns the result of e raised to the power of a given exponent. This function is commonly used in mathematical and scientific calculations.

• `ERF`

The `ERF` function calculates the error function of a given value. The error function returns the probability of a normal variable with a mean of zero and a standard deviation of one falling between two values. This function is commonly used in statistics and engineering applications.

You can learn more about the `GAMMALN` Google Sheets function on Google Support.