''' Purpose: naming allows abstraction
    Author:  Jim Cohoon
    ID:      jpc
'''

# get access to Python math comutational resources
import math

# There are several libraries we can import so we can use
# things defined in those libraries in our programs!
# Variables, functions, and other stuff are in those libraries and
# math library is one of them.

# import!! import says "hey I wanna use another library so give
# me access" and when we use it we do
# libraryname.whateverwewannause (this is the format not what
# you actually type) like math.pi
# . operator is selecting from the library

# demonstrate the two math constants
print( 'Python approximation of pi:', math.pi )
print( 'Python approximation of Euler\'s number:', math.e )

# Why won't calculations be perfect in Python? They're approximations
# up to 15 digits! *important*
print()
print()

# show some math computation
a = math.radians( 30 )
b = math.radians( 45 )

# Why did I do a = math.radians ( 30 )? To store whatever
# the result of math.radians(30) is in a.
# If I just called the function then it executes but I didn't
# store it anywhere.
# .radians() is an ex of a function from the math library. It takes in
# a number in degrees and gives you the radians equivalent.
sin_a = math.sin( a )
tan_b = math.tan( b )
# .sin() will give you the sin of whatever angle (radians) you pass into it.
# .tan() will give you the tan of whatever angle (radians) you pass into it.

print( 'sin( 30 degrees ):', sin_a )
print( 'tan( 45 degrees ):', tan_b )