Merge pull request #1127 from kenarab/patch-1

Update geometric.hpp

Author: mborland

include/boost/math/distributions/geometric.hpp

@@ -384,6 +384,8 @@ namespace boost
     inline RealType logcdf(const geometric_distribution<RealType, Policy>& dist, const RealType& k)
     { // Cumulative Distribution Function of geometric.
       using std::pow;
+      using std::log;
+      using std::exp;
       static const char* function = "boost::math::logcdf(const geometric_distribution<%1%>&, %1%)";
 
       // k argument may be integral, signed, or unsigned, or floating point.