diff --git a/maths.cpp b/maths.cpp
index 4c7fe55e..8891d707 100644
--- a/maths.cpp
+++ b/maths.cpp
@@ -73,18 +73,6 @@ template uint32_t util::log2 (uint32_t);
 template uint64_t util::log2 (uint64_t);
 
 
-///////////////////////////////////////////////////////////////////////////////
-template <typename T>
-double
-util::rootsquare (T a, T b)
-    { return sqrt (util::pow2 (a) + util::pow2 (b)); }
-
-
-//-----------------------------------------------------------------------------
-template double util::rootsquare (double, double);
-template double util::rootsquare (   int,    int);
-
-
 ///////////////////////////////////////////////////////////////////////////////
 template <typename T>
 bool
diff --git a/maths.hpp b/maths.hpp
index d9f0a7f6..3f01979f 100644
--- a/maths.hpp
+++ b/maths.hpp
@@ -80,13 +80,6 @@ namespace util {
     log2up  (T val);
 
 
-    ///////////////////////////////////////////////////////////////////////////////
-    // Roots
-    template <typename T>
-    double
-    rootsquare  (T a, T b);
-
-
     ///////////////////////////////////////////////////////////////////////////////
     // Rounding
     template <typename T, typename U>
diff --git a/test/maths.cpp b/test/maths.cpp
index 6d449bc3..24077983 100644
--- a/test/maths.cpp
+++ b/test/maths.cpp
@@ -143,8 +143,6 @@ main (void)
 
     tap.expect_eq (util::pow2 (4u), 16u, "pow2");
 
-    tap.expect_eq (util::rootsquare (2, 2), sqrt (8), "rootsquare");
-
     static const double POS_ZERO =  1.0 / numeric_limits<double>::infinity ();
     static const double NEG_ZERO = -1.0 / numeric_limits<double>::infinity ();