X-Git-Url: http://gitweb.michael.orlitzky.com/?a=blobdiff_plain;f=src%2FIntegration%2FTrapezoid.hs;h=06350fcf54a70da55ac317610c1a7dca2f3b8a62;hb=c160f3101ddb9797fd30007d6f628da394628538;hp=444d92d2eb9a0ed2e6911970f54cd88aafd71b3a;hpb=2f54e89d36e835c58efcc281741632d457859b20;p=numerical-analysis.git

diff --git a/src/Integration/Trapezoid.hs b/src/Integration/Trapezoid.hs
index 444d92d..06350fc 100644
--- a/src/Integration/Trapezoid.hs
+++ b/src/Integration/Trapezoid.hs
@@ -38,8 +38,9 @@ trapezoid_1 :: (Field.C a, ToRational.C a, Field.C b)
             -> a       -- ^ The \"right\" endpoint, @b@
             -> b
 trapezoid_1 f a b =
-  (((f a) + (f b)) / 2) * (fromRational' $ toRational (b - a))
-
+  (((f a) + (f b)) / 2) * coerced_interval_length
+  where
+    coerced_interval_length = fromRational' $ toRational (b - a)
 
 -- | Use the composite trapezoid rule to numerically integrate @f@
 --   over @n@ subintervals of [@a@, @b@].