View Compilation Error

0_0_33838687_4452.cpp: In function 'double mul(double, double*, double*, double, double, double)':
0_0_33838687_4452.cpp:7:32: error: 'pow' was not declared in this scope
     return 1.0/3*a*pow(k-x[0],3)+y[0]*k-0.5*k2*k*k-b*k;
                                ^
0_0_33838687_4452.cpp: In function 'void solve(double*, double*)':
0_0_33838687_4452.cpp:15:53: error: 'fabs' was not declared in this scope
     ans=fabs(mul(a,x,y,x[2],k,b)-mul(a,x,y,x[1],k,b));
                                                     ^