View Compilation Error

0_0_18057395_26542.cpp:28:13: error: 'int cos [300100]' redeclared as different kind of symbol
 int cos[maxn];
             ^
In file included from GCC4.9.2/x86_64-w64-mingw32/include/c++/cmath:44:0,
                 from GCC4.9.2/x86_64-w64-mingw32/include/c++/random:38,
                 from GCC4.9.2/x86_64-w64-mingw32/include/c++/bits/stl_algo.h:66,
                 from GCC4.9.2/x86_64-w64-mingw32/include/c++/algorithm:62,
                 from 0_0_18057395_26542.cpp:4:
GCC4.9.2/x86_64-w64-mingw32/include/math.h:139:18: note: previous declaration 'double cos(double)'
   double __cdecl cos(double _X);
                  ^
0_0_18057395_26542.cpp: In function 'int main()':
0_0_18057395_26542.cpp:80:48: error: invalid types '<unresolved overloaded function type>[int]' for array subscript
         for(int i=1;i<=n;++i) scanf("%d",&cos[i]);
                                                ^
0_0_18057395_26542.cpp:91:27: error: invalid types '<unresolved overloaded function type>[int]' for array subscript
             ans+=(LL)cos[i]*(dp1[i]+dp2[i]);
                           ^