diff --git a/README.md b/README.md
index 798b1af..ba4cebc 100644
--- a/README.md
+++ b/README.md
@@ -57,15 +57,10 @@ together with functions for
  - ln (natural log)
  - log10 (base-10 log)
  - log2 (base-2 log)
- - negative (reverse signs of both real and imaginary values)
  
 ---
 
 Planned additional functionality, but still to implement
 
  * pow (power)
- - haversine (haversine)
- - inversehaversine (inverse haversine)
- - gudermannian (gudermannian)
- - inversegudermannian (inverse gudermannian)
  
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