diff --git a/CHANGES.markdown b/CHANGES.markdown
--- a/CHANGES.markdown
+++ b/CHANGES.markdown
@@ -1,3 +1,12 @@
+0.6.0.2 (28 March 2013)
+-----------------------
+
+* bump upper bound to allow `NumInstances-1.2`
+
+* Quadratic solver is now more numerically stable, getting rid of some
+  incorrect behavior of `juxtapose`
+  ([\#46](https://github.com/diagrams/diagrams-lib/issues/46))
+
 0.6.0.1: 7 January 2013
 -----------------------
 
diff --git a/diagrams-lib.cabal b/diagrams-lib.cabal
--- a/diagrams-lib.cabal
+++ b/diagrams-lib.cabal
@@ -1,5 +1,5 @@
 Name:                diagrams-lib
-Version:             0.6.0.1
+Version:             0.6.0.2
 Synopsis:            Embedded domain-specific language for declarative graphics
 Description:         Diagrams is a flexible, extensible EDSL for creating
                      graphics of many types.  Graphics can be created
@@ -68,7 +68,7 @@
                        diagrams-core >= 0.6 && < 0.7,
                        active >= 0.1 && < 0.2,
                        vector-space >= 0.7.7 && < 0.9,
-                       NumInstances >= 1.0 && < 1.1,
+                       NumInstances >= 1.0 && < 1.3,
                        colour >= 2.3.2 && < 2.4,
                        data-default >= 0.2 && < 0.6,
                        pretty >= 1.0.1.2 && < 1.2,
diff --git a/src/Diagrams/Solve.hs b/src/Diagrams/Solve.hs
--- a/src/Diagrams/Solve.hs
+++ b/src/Diagrams/Solve.hs
@@ -43,8 +43,10 @@
     -- multiplicity 2 solution
   | d == 0    = [-b/(2*a)]
 
-  | otherwise = [(-b + sqrt d)/(2*a), (-b - sqrt d)/(2*a)]
+    -- see http://www.mpi-hd.mpg.de/astrophysik/HEA/internal/Numerical_Recipes/f5-6.pdf
+  | otherwise = [q/a, c/q]
  where d = b*b - 4*a*c
+       q = -1/2*(b + signum b * sqrt d)
 
 quadForm_prop :: Double -> Double -> Double -> Bool
 quadForm_prop a b c = all (aboutZero . eval) (quadForm a b c)