"""
Exercise 7.1 from "A primer on...
Make a class for representing a 
parameterized function.
"""

import numpy as np

class F:
    def __init__(self, a, w):
        self.a = a
        self.w = w

    def value(self, x):
        return np.exp(-self.a * x) * np.sin(self.w * x)



f = F(a=1.0, w=0.1)
print(f.value(x=np.pi))
#0.013353835137
f.a = 2
print(f.value(x=np.pi))
#0.00057707154012

"""
Terminal> python F.py 
0.01335383513703555
0.0005770715401197441
"""