View Compilation Error

0_0_22872145_18990.c: In function 'main':
0_0_22872145_18990.c:6:25: error: expected expression before 'double'
         double a1 = pow(double(K),2./3), a2 = 1,atp;
                         ^
0_0_22872145_18990.c:6:21: error: too few arguments to function 'pow'
         double a1 = pow(double(K),2./3), a2 = 1,atp;
                     ^