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## Sigmoid Activation Function Understanding (easy)

#### Example

## Understanding the Sigmoid Activation Function

The sigmoid activation function is crucial in neural networks, especially for binary classification tasks. It maps any real-valued number into the (0, 1) interval, making it useful for modeling probability as an output.
### Mathematical Definition

The sigmoid function is mathematically defined as:
\[
\sigma(z) = \frac{1}{1 + e^{-z}}
\]
Where \(z\) is the input to the function.
### Characteristics

Write a Python function that computes the output of the sigmoid activation function given an input value z. The function should return the output rounded to four decimal places.

Example: input: z = 0 output: 0.5 reasoning: The sigmoid function is defined as σ(z) = 1 / (1 + exp(-z)). For z = 0, exp(-0) = 1, hence the output is 1 / (1 + 1) = 0.5.

**Output Range:**The output is always between 0 and 1.**Shape:**It has an "S" shaped curve.**Gradient:**The function's gradient is highest near \(z = 0\) and decreases toward either end of the z-axis.

import math def sigmoid(z: float) -> float: result = 1 / (1 + math.exp(-z)) return round(result, 4)

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