# log2

log2(x)

Compute the logarithm of `x` to base 2. Throws `DomainError` for negative `Real` arguments.

## Examples

1. Calculate log base 2 of a positive number:

``````julia> log2(8)
3.0``````

This example calculates the logarithm base 2 of the number 8, which is 3.

2. Calculate log base 2 of a fraction:

``````julia> log2(0.5)
-1.0``````

The `log2` function can handle fractional inputs. In this example, it computes the logarithm base 2 of the fraction 0.5, which is -1.

3. Throw an error for negative real numbers:
``````julia> log2(-10.0)
ERROR: DomainError with -10.0:
log2 will only return a complex result if called with a complex argument. Try log2(complex(x)).``````

The `log2` function throws a `DomainError` when called with a negative real number. It suggests using `log2(complex(x))` if a complex result is desired.

Common mistake example:

``````julia> log2(-5)
ERROR: DomainError with -5:
log2 will only return a complex result if called with a complex argument. Try log2(complex(x)).``````

In this example, the `log2` function is called with a negative integer, which results in a `DomainError`. Remember that `log2` is only defined for positive real numbers.