View Compilation Error

0_0_12835923_10883.cpp:7: error: `acos' was not declared in this scope
0_0_12835923_10883.cpp: In function `double dist(point, point)':
0_0_12835923_10883.cpp:27: error: `sqrt' undeclared (first use this function)
0_0_12835923_10883.cpp:27: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_12835923_10883.cpp: In function `int main()':
0_0_12835923_10883.cpp:63: error: `cos' undeclared (first use this function)
0_0_12835923_10883.cpp:63: error: `sin' undeclared (first use this function)