Arc Tangents and Equation For one of the problems in my book, it requires you to put the arc tangent into the 2piK equation and solve for the arc tangents and lie in [0,2pi].  For:
arctan(117)+piK
the answers are 1.5622 and 4.70384, how is the 4.70384 found??

$1.5622+\pi\approx 4.70384{}{}{}{}{}{}$
Adding or subtracting any other multiples of $\pi$ gives you values outside of the range $[0,2\pi]$, so those are the only answers.
