University of South Carolina High School Math Contest/1993 Exam/Problem 10
Problem
Arcsin(1/3) + Arccos(1/3) + Arctan(1/3) + Arccot(1/3) =
Solution
If we construct right triangles for each pair of arguments ( and $\arctan, \arccot$ (Error compiling LaTeX. Unknown error_msg)), we see that the sum of the angles is .