fixed point added
Exercise 1.35 added
Exercise 1.36 added
search root added
Exercise 1.37 added
Exercise 1.41 added
Exercise 1.42 added
Exercise 1.43 added
Exercise 1.44 added
Exercise 1.46 added
rational number operations
using gcd() to reduce numbers
Exercise 2.1 added
add some comments
Exercise 2.17 added