# Python | math.cos() function

In Python, math module contains a number of mathematical operations, which can be performed with ease using the module. `math.cos()` function returns the cosine of value passed as argument. The value passed in this function should be in radians.

Syntax: math.cos(x)

Parameter:
x : value to be passed to cos()

Returns: Returns the cosine of value passed as argument

Code #1:

 `# Python code to demonstrate the working of cos() ` `    `  `# importing "math" for mathematical operations  ` `import` `math  ` `   `  `a ``=` `math.pi ``/` `6` `    `  `# returning the value of cosine of pi / 6  ` `print` `(``"The value of cosine of pi / 6 is : "``, end ``=``"")  ` `print` `(math.cos(a))  `

Output:

```The value of cosine of pi/6 is : 0.8660254037844387
```

Code #2:

 `# Python program showing  ` `# Graphical representation of  ` `# cos() function  ` `import` `math ` `import` `numpy as np ` `import` `matplotlib.pyplot as plt  ` ` `  `in_array ``=` `np.linspace(``-``(``2` `*` `np.pi), ``2` `*` `np.pi, ``20``) ` ` `  `out_array ``=` `[] ` ` `  `for` `i ``in` `range``(``len``(in_array)): ` `    ``out_array.append(math.cos(in_array[i])) ` `    ``i ``+``=` `1` ` `  `  `  `print``(``"in_array : "``, in_array)  ` `print``(``"\nout_array : "``, out_array)  ` ` `  `# red for numpy.sin()  ` `plt.plot(in_array, out_array, color ``=` `'red'``, marker ``=` `"o"``)  ` `plt.title(``"math.cos()"``)  ` `plt.xlabel(``"X"``)  ` `plt.ylabel(``"Y"``)  ` `plt.show()  `

Output:

in_array : [-6.28318531 -5.62179738 -4.96040945 -4.29902153 -3.6376336 -2.97624567
-2.31485774 -1.65346982 -0.99208189 -0.33069396 0.33069396 0.99208189
1.65346982 2.31485774 2.97624567 3.6376336 4.29902153 4.96040945
5.62179738 6.28318531]

out_array : [1.0, 0.7891405093963934, 0.2454854871407988, -0.40169542465296987, -0.8794737512064891, -0.9863613034027223, -0.6772815716257412, -0.08257934547233249, 0.5469481581224268, 0.9458172417006346, 0.9458172417006346, 0.5469481581224268, -0.0825793454723316, -0.6772815716257405, -0.9863613034027223, -0.8794737512064893, -0.40169542465296987, 0.2454854871407988, 0.7891405093963934, 1.0] Attention geek! Strengthen your foundations with the Python Programming Foundation Course and learn the basics.

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