1. The problem statement, all variables and given/known data -arctan(x/y) = arctan(y/x) ? Are they equivalent? I can't find anything online and I have seen that my solution to some problem involves -arctan(x/y) and it agrees with Wolfram Alpha. On the other hand, my professor's solution shows the arctan(y/x) and this is why I am doubtful. Any ideas? Thank you.