# How to calculate the cross product in Python

To calculate the cross product between two vectors in the python language use the cross() function in the numpy module.

**numpy.cross(v1,v2)**

Arguments v1 and v2 are two arrays.

The function returns the cross product v1 x v2.

**What is the cross product?** The cross product is a vector v1 × v2 which has the null modulus (zero length) when the two vectors v1 and v2 have the same direction.

## Example

Import the NumPy library

import numpy as np

Definire due vettori (array).

a = np.array([1,2,3], float)

b = np.array([4,5,6], float)

Use the **cross()** function to calculate the cross product

np.cross(a,b)

The result is the cross product a × b

array([-3., 6., -3.])

The cross product a × b is a vector orthogonal to both the vector v1 and the vector v2.

**Example 2**

Define two vectors with the same direction

a = np.array([2,0,0], float)

b = np.array([4,0,0], float)

Calculate the cross product

np.cross(a,b)

In this case the cross product a × b is a null vector because they have the same direction

array([0., 0., 0.])

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