View Compilation Error

0_0_27473474_27792.cpp: In function 'int main()':
0_0_27473474_27792.cpp:14:16: error: 'sqrt' was not declared in this scope
   v0=sqrt(2*g*h);
                ^
0_0_27473474_27792.cpp:15:23: error: 'atan2' was not declared in this scope
   double ans=atan2(b,a);
                       ^
0_0_27473474_27792.cpp:16:16: error: 'cos' was not declared in this scope
   v1=v0*cos(ans),v2=v0*sin(ans);
                ^
0_0_27473474_27792.cpp:16:31: error: 'sin' was not declared in this scope
   v1=v0*cos(ans),v2=v0*sin(ans);
                               ^