Index: boost/math/constants/calculate_constants.hpp
===================================================================
--- boost/math/constants/calculate_constants.hpp	(revision 81155)
+++ boost/math/constants/calculate_constants.hpp	(working copy)
@@ -157,7 +157,7 @@
    // This is the method described in:
    // "Some New Algorithms for High-Precision Computation of Euler's Constant"
    // Richard P Brent and Edwin M McMillan.
-   // Mathematics of Comnputation, Volume 34, Number 149, Jan 1980, pages 305-312.
+   // Mathematics of Computation, Volume 34, Number 149, Jan 1980, pages 305-312.
    // See equation 17 with p = 2.
    //
    T n = 3 + (M ? (std::min)(M, tools::digits<T>()) : tools::digits<T>()) / 4;
@@ -929,7 +929,7 @@
 template<int N>
 inline T constant_rayleigh_kurtosis_excess<T>::compute(BOOST_MATH_EXPLICIT_TEMPLATE_TYPE_SPEC(mpl::int_<N>))
 { // - (6 Pi^2 - 24 Pi + 16)/((Pi - 4)^2)
-    // Might provide provide and calculate this using pi_minus_four.
+    // Might provide and calculate this using pi_minus_four.
    BOOST_MATH_STD_USING
    return - (((static_cast<T>(6) * pi<T, policies::policy<policies::digits2<N> > >()
         * pi<T, policies::policy<policies::digits2<N> > >())
@@ -944,7 +944,7 @@
 template<int N>
 inline T constant_rayleigh_kurtosis<T>::compute(BOOST_MATH_EXPLICIT_TEMPLATE_TYPE_SPEC(mpl::int_<N>))
 { // 3 - (6 Pi^2 - 24 Pi + 16)/((Pi - 4)^2)
-  // Might provide provide and calculate this using pi_minus_four.
+  // Might provide and calculate this using pi_minus_four.
    BOOST_MATH_STD_USING
    return static_cast<T>(3) - (((static_cast<T>(6) * pi<T, policies::policy<policies::digits2<N> > >()
         * pi<T, policies::policy<policies::digits2<N> > >())