# Python cos

The Python cos function is one of the Python Math function, which calculates the Trigonometry Cosine for the specified expression. The Python cos function returns the value between -1 and 1. In this section, we discuss how to use math cos function with example.

The mathematical formula behind the Python Trigonometry Cosine function is

COS(x) = Length of the Adjacent Side / Length of the Hypotenuse

The syntax of the cos Function in Python Programming Language is

`math.cos(number);`

Number: It can be a number or a valid numerical expression for which you want to find Cosine value.

• If the number argument is a positive or negative number, the cos function returns the Cosine value.
• If it is not a number, the cos function returns TypeError.

## Python cos Function Example

The Python cos Function allows finding the trigonometry Cosine for the numeric values. In this example, we are going to find the Cosine values of different data types and display the output.

TIP: Please refer Python acos Function article to find the Arc Cosine of the specified Python expression.

```# Python cos Function

import math

Tup = (1, 2, 3, -4 , 5)
Lis = [-1, 2, -3.5, -4 , 5]

print('Cosine value of Positive Number = %.2f' %math.cos(10))
print('Cosine value of Negative Number = %.2f' %math.cos(-15))

print('Cosine value of Tuple Item = %.2f' %math.cos(Tup))
print('Cosine value of List Item = %.2f' %math.cos(Lis))

print('Cosine value of Multiple Number = %.2f' %math.cos(10 + 20 - 40))
print('Cosine value of String Number = ', math.cos('Hello'))```

First, We declared Python List and Tuple with some random values. Next, we used the cos Function directly on both the Positive integer and negative integer. The following statements find the Cosine of the corresponding values.

```print('Cosine value of Positive Number = %.2f' %math.cos(10))
print('Cosine value of Negative Number = %.2f' %math.cos(-15))```

Next, We used the cos Function on Tuple and List items. If you see the above screenshot, the Python cos function is working perfectly on them.

```print('Cosine value of Tuple Item = %.2f' %math.cos(Tup))
print('Cosine value of List Item = %.2f' %math.cos(Lis))```

Next, We used the cos Math function on multiple values.

`print('Cosine value of Multiple Number = %.2f' %math.cos(10 + 20 - 40))`

Within the last statement, we tried cos Function on the String value, and it returns TypeError.

`print('Cosine value of String Number = ', math.cos('Hello'))`