View Compilation Error

0_0_6006725_27038.cpp:5: error: `acos' was not declared in this scope
0_0_6006725_27038.cpp: In function `double Norm(const point&, const point&)':
0_0_6006725_27038.cpp:22: error: `sqrt' undeclared (first use this function)
0_0_6006725_27038.cpp:22: error: (Each undeclared identifier is reported only once for each function it appears in.)