# How to calculate a tangent for a given angle in python ?

Published: April 13, 2021

Tags: Python; Math;

Examples of how to calculate and plot a tangent function in python

### Calculate a tangent for a given angle

To get the tangent of a given angle a solution is to use the module math, for example

````import math`

`angle = 0`

`math.tan(angle)`
```

returns

````0`
```

Note: the tan function assumes that the input is in radian. To convert degree to radian a solution is to use math.radians()

````angle = 45 # angle in degree`
`angle = math.radians(angle) # angle in radian`
```

Another example

````angle = math.pi / 6`

`math.tan(angle)`
```

returns

````0.5773502691896256`
```

Note: to round a float in python, a solution is to use round():

````round( math.tan(angle), 2 )`
```

gives

````0.58`
```

### Plot a tangent function

````import matplotlib.pyplot as plt`
`import numpy as np`

`angle_min = - 2.0 * math.pi`
`angle_max = 2.0 * math.pi`
`res = 0.01`

`angle_list = [a for a in np.arange(angle_min,angle_max,res)]`
`angle_tan_list = [math.tan(a) for a in angle_list]`

`plt.plot(angle_list, angle_tan_list)`

`plt.title("How to calculate a tangent for a given angle in python ?",fontsize=12)`

`plt.ylim(-10,10)`

`plt.savefig("tangent_function_01.png", bbox_inches='tight', dpi=100)`

`plt.show()`
```

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