Update my answers in ch2

Author: dwayne

ch2/ex1.txt

@@ -1,3 +1,5 @@
+Exercises: Comprehension Check
+
 1.
 
 Given,
@@ -7,9 +9,13 @@ square x = x * x
 
 Then, in the REPL we write them as
 
-let half x = x /2
+let half x = x / 2
 let square x = x * x
 
 2.
 
 areaOfCircle r = 3.14 * (r * r)
+
+3.
+
+areaOfCircle r = pi * (r * r)

ch2/ex2.txt

@@ -1,3 +1,5 @@
+Exercises: Parentheses and Association
+
 1.
 
 a) 8 + 7 * 9   = 8 + (7 * 9) = 71

ch2/ex3.txt

@@ -1,7 +1,13 @@
+Exercises: Heal the Sick
+
 1. let area x = 3.14 * (x * x)
 
 2. let double x = x * 2
 
+or
+
+let double b = b * 2
+
 3.
 
 x = 7

ch2/ex4.txt

@@ -1,3 +1,5 @@
+Exercises: A Head Code
+
 1. let x = 5 in x; 5
 2. let x = 5 in x * x; 25
 3. let x = 5; y = 6 in x * y; 30

ch2/learn.hs

@@ -0,0 +1,13 @@
+-- learn.hs
+
+module Learn where
+-- First, we declare the name of our module so
+-- it can be imported by name in a project.
+-- We won't be doing a project of this size
+-- for a while yet.
+
+x = 10 * 5 + y
+
+myResult = x * 5
+
+y = 10