5.4. Math functions¶
Python has a
math module that provides most of the familiar
mathematical functions. Before we can use the module, we have to import
>>> import math
This statement creates a module object named math. If you print the module object, you get some information about it:
The module object contains the functions and variables defined in the module. To access one of the functions, you have to specify the name of the module and the name of the function, separated by a dot (also known as a period). This format is called dot notation.
The first example computes the logarithm base 10 of the signal-to-noise
ratio. The math module also provides a function called
that computes logarithms base e.
The second example finds the sine of
radians. The name of
the variable is a hint that
sin and the other trigonometric
tan, etc.) take arguments in
radians. To convert from degrees to radians, divide by 360 and multiply
math.pi gets the variable
from the math module. The value of this variable is an approximation of
pi, accurate to about 15 digits.
If you know your trigonometry, you can check the previous result by comparing it to the square root of two divided by two: