diff --git a/metric.cabal b/metric.cabal
--- a/metric.cabal
+++ b/metric.cabal
@@ -1,5 +1,5 @@
 name:                metric
-version:             0.1.4
+version:             0.2.0
 synopsis:            Metric spaces.
 license:             MIT
 license-file:        LICENSE
diff --git a/src/Data/Metric.hs b/src/Data/Metric.hs
--- a/src/Data/Metric.hs
+++ b/src/Data/Metric.hs
@@ -6,7 +6,6 @@
   RestrictedDamerauLevenshtein(..),
   Euclidean(..),
   Taxicab(..),
-  Cosine(..),
   Chebyshev(..),
   PostOffice(..)
 ) where
@@ -14,4 +13,4 @@
 import Data.Metric.Class (Metric(..))
 import Data.Metric.Set (Discrete(..))
 import Data.Metric.String (Hamming(..), Levenshtein(..), RestrictedDamerauLevenshtein(..)) 
-import Data.Metric.Vector.Real (Euclidean(..), Taxicab(..), Cosine(..), Chebyshev(..), PostOffice(..))
+import Data.Metric.Vector.Real (Euclidean(..), Taxicab(..), Chebyshev(..), PostOffice(..))
diff --git a/src/Data/Metric/Vector/Real.lhs b/src/Data/Metric/Vector/Real.lhs
--- a/src/Data/Metric/Vector/Real.lhs
+++ b/src/Data/Metric/Vector/Real.lhs
@@ -5,15 +5,14 @@
 > module Data.Metric.Vector.Real (
 >   Euclidean(..),
 >   Taxicab(..),
->   Cosine(..),
 >   Chebyshev(..),
 >   PostOffice(..)
 > ) where
 > 
-> import Prelude hiding (zipWith, map, foldr1, maximum, length)
+> import Prelude hiding (zipWith, map, maximum, length, sum)
 > import Data.Function (on)
 > import Data.Packed.Matrix.Extras (fromVectors)
-> import Data.Vector (Vector(..), zipWith, map, foldr1, maximum, length)
+> import Data.Vector (Vector(..), zipWith, map, maximum, length, sum)
 > import Data.Vector.Extras (zero)
 > import Numeric.LinearAlgebra.Algorithms (rank)
 > import Data.Metric.Class (Metric(..))
@@ -33,7 +32,7 @@
 >   } deriving (Eq, Show)
 > 
 > instance Metric Euclidean where
->   distance = sqrt . foldr1 (+) . map (**2) <$$> zipWith (-) `on` getEuclidean
+>   distance = sqrt . sum . map (**2) <$$> zipWith (-) `on` getEuclidean
 
 `Taxicab` describes the length of the path connecting the two vectors
 along only vertical and horizontal lines (`_|`) without backtracing.
@@ -45,36 +44,7 @@
 >   } deriving (Eq, Show)
 > 
 > instance Metric Taxicab where
->   distance = foldr1 (+) . map abs <$$> zipWith (-) `on` getTaxicab
- 
-`Cosine` wraps cosine similarity, measuring the cosine of the angle
-between two vectors using the Euclidean dot product formula. Unlike the
-other distance functions, this describes orientation, rather than
-magnitude; this is useful when comparing tf-idf weights, as it
-implicitly normalises for document length.
-
-Edge case: the denominator of this function is the product of the
-vectors norms; when either of the vectors have no magnitude, this
-describes division by zero. A runtime error occurs in this case.
-
-> newtype Cosine = Cosine
->   { getCosine :: Vector Double
->   } deriving (Eq, Show)
-> 
-> instance Metric Cosine where
->   Cosine v0 <-> Cosine v1 
->     | norm == 0 = error "zero magnitude vector"
->     | otherwise = (v0 `dot` v1) / norm
->     where norm = (v0 |*| v1)
->
-> mag :: Vector Double -> Double
-> mag = sqrt . foldr1 (+) . map (**2)
->
-> dot :: Vector Double -> Vector Double -> Double
-> dot = foldr1 (+) <$$> zipWith (*)
->
-> (|*|) :: Vector Double -> Vector Double -> Double
-> (|*|) = (*) `on` mag
+>   distance = sum . map abs <$$> zipWith (-) `on` getTaxicab
 
 `Chebyshev` wraps Chebyshev distance, in which the distance between two
 vectors is defined to be the maximum of their differences along any
@@ -111,3 +81,6 @@
 >
 > (|+|) :: Vector Double -> Vector Double -> Double
 > (|+|) = (+) `on` mag
+>
+> mag :: Vector Double -> Double
+> mag = sqrt . sum . map (**2)
diff --git a/test/Main.hs b/test/Main.hs
--- a/test/Main.hs
+++ b/test/Main.hs
@@ -1,6 +1,6 @@
 import Data.Metric.Set (Discrete(..))
 import Data.Metric.String (Hamming(..), Levenshtein(..), RestrictedDamerauLevenshtein(..))
-import Data.Metric.Vector.Real (Euclidean(..), Taxicab(..), Cosine(..), Chebyshev(..), PostOffice(..))
+import Data.Metric.Vector.Real (Euclidean(..), Taxicab(..), Chebyshev(..), PostOffice(..))
 import Control.Applicative ((<$>))
 import Data.Vector (Vector(..), fromList)
 import Data.Ratio ((%))
@@ -36,16 +36,6 @@
 prop_TaxicabMetric :: Taxicab -> Taxicab -> Taxicab -> Property
 prop_TaxicabMetric = prop_Metric
 
--- | Cosine
-
-instance Arbitrary Cosine where
-  arbitrary = oneof [choose (1,1000), choose (-1,-1000)]
-          >>= vectorOf 3 . return . fromRational . (%100)
-          >>= return . Cosine . fromList
-
-prop_CosineMetric :: Cosine -> Cosine -> Cosine -> Property
-prop_CosineMetric = prop_Metric
-
 -- | Chebyshev
 
 instance Arbitrary Chebyshev where
@@ -93,7 +83,6 @@
   [ testProperty "discrete"    $ prop_DiscreteMetric
   , testProperty "euclidean"   $ prop_EuclideanMetric
   , testProperty "taxicab"     $ prop_TaxicabMetric
-  , testProperty "cosine"      $ prop_CosineMetric
   , testProperty "chebyshev"   $ prop_ChebyshevMetric
   , testProperty "postoffice"  $ prop_PostOfficeMetric
   , testProperty "hamming"     $ prop_HammingMetric