README.md in dydx-0.0.1 vs README.md in dydx-0.0.2

@@ -1,9 +1,34 @@
 # Dydx
+It always happens you want to differentiate with ruby. right?
 
-TODO: Write a gem description
+Dydx will eliminate this. Like this
 
+```
+( d/dx(e ^ :x) ).to_s
+=> "( e ^ x )"
+
+$y = cos(:x)
+(dy/dx).to_s
+=> "( - sin( x ) )"
+
+# pretermit '.to_s'
+
+d/dx(log(:x))
+=> "( 1 / x )"
+
+d/dx(:x^:n)
+=> "( n * ( x ^ ( n - 1 ) ) )"
+
+
+d/dx(:x^2)
+=> "( 2 * x )"
+
+```
+
+(That's wonderful!!!!! But, I feel there is no meaning ... )
+
 ## Installation
 
 Add this line to your application's Gemfile:
 
     gem 'dydx'
@@ -16,10 +41,10 @@
 
     $ gem install dydx
 
 ## Usage
 
-TODO: Write usage instructions here
+    include Dydx
 
 ## Contributing
 
 1. Fork it ( https://github.com/[my-github-username]/dydx/fork )
 2. Create your feature branch (`git checkout -b my-new-feature`)