Update README

Author: devmotion

README.md

@@ -1,2 +1,29 @@
 # IrrationalConstants.jl
-defines additional mathematical constants
+
+This package defines the following irrational constants:
+
+```julia
+twoπ       # 2π
+fourπ      # 4π
+halfπ      # π / 2
+quartπ     # π / 4
+invπ       # 1 / π
+twoinvπ    # 2 / π
+fourinvπ   # 4 / π
+inv2π      # 1 / (2π)
+inv4π      # 1 / (4π)
+sqrt2      # √2
+sqrt3      # √3
+sqrtπ      # √π
+sqrt2π     # √2π
+sqrt4π     # √4π
+sqrthalfπ  # √(π / 2)
+invsqrt2   # 1 / √2
+invsqrt2π  # 1 / √2π
+loghalf    # log(1 / 2)
+logtwo     # log(2)
+logπ       # log(π)
+log2π      # log(2π)
+log4π      # log(4π)
+```
+