# digamma

digamma(x)

Compute the digamma function of `x` (the logarithmic derivative of `gamma(x)`)

## Examples

``````julia> using SpecialFunctions

julia> digamma(2)
0.42278433509846713

julia> digamma(0.5)
-1.9635100260214235``````
1. Calculate the digamma function of a positive number:

``````julia> digamma(3.7)
0.6471423733718684``````

This example calculates the digamma function of the number 3.7.

2. Calculate the digamma function of a negative number:

``````julia> digamma(-2.5)
-0.5240777691836912``````

The `digamma` function can also handle negative numbers. This example calculates the digamma function of -2.5.

3. Calculate the digamma function of a complex number:
``````julia> digamma(1 + 2im)
0.42278433509846713 - 1.5707963267948966im``````

The `digamma` function can be applied to complex numbers as well. This example calculates the digamma function of the complex number 1 + 2im.

Common mistake example:

``````julia> digamma(0)
ERROR: DomainError with -Inf result``````

In this example, the function call `digamma(0)` leads to a `DomainError` because the digamma function is not defined for zero. It's important to ensure that the input values are within the valid domain to avoid such errors.