View Compilation Error

0_0_36067179_10071.cpp: In function 'long long int geometric(long long int, long long int)':
0_0_36067179_10071.cpp:26:14: error: 'a2' was not declared in this scope
  long long p=a2/a1;
              ^
0_0_36067179_10071.cpp:26:17: error: 'a1' was not declared in this scope
  long long p=a2/a1;
                 ^
0_0_36067179_10071.cpp:27:44: error: 'k' was not declared in this scope
     long long  temp = ((a1%mod)*(pow_mod(p,k-1,mod)))%mod;
                                            ^
0_0_36067179_10071.cpp:27:51: error: 'pow_mod' was not declared in this scope
     long long  temp = ((a1%mod)*(pow_mod(p,k-1,mod)))%mod;
                                                   ^