How did you type the squares? The full form of your x^2
gives x\262
. The two expressions are not totally equivalent on the negative real line:
{Arg[x + I y], 2 ArcTan[y/(x + Sqrt[x^2 + y^2])]} /. {x -> -1,
y -> 0}
I suppose the two functions Arg
and ArcTan
are meant for complex and real usage, not a mixture. However, it is disappointing that the simplification does not work.