View Compilation Error

0_0_30702019_6408.cpp: In function 'int main()':
0_0_30702019_6408.cpp:9:49: error: 'pow' was not declared in this scope
  s = n*n*n*n*n*n / 2 - 7 * n*n*n/2 + 3 * pow(n,2);
                                                 ^