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Python | math.cos() function
• Difficulty Level : Medium
• Last Updated : 20 Mar, 2019

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]

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