View Compilation Error

0_0_39192454_15483.cpp: In function 'double angle(double, double, double)':
0_0_39192454_15483.cpp:8:16: error: 'acos' was not declared in this scope
    8 |         return acos(ans);
      |                ^~~~
0_0_39192454_15483.cpp: In function 'int main()':
0_0_39192454_15483.cpp:21:38: error: 'sin' was not declared in this scope
   21 |                 V = a * b * c * sqrt(sin(W) * sin(W - A) * sin(W - B) * sin(W - C));
      |                                      ^~~
0_0_39192454_15483.cpp:21:33: error: 'sqrt' was not declared in this scope
   21 |                 V = a * b * c * sqrt(sin(W) * sin(W - A) * sin(W - B) * sin(W - C));
      |                                 ^~~~