Arctan​(AngouriMath.​Entity)

using System;
using static AngouriMath.MathS;
var expr = Arcsin("x") + Arccos("x");
Console.WriteLine(expr);
var expr2 = Arcsin(Sin("x")) + Arccos(Cos("y"));
Console.WriteLine(expr2);
Console.WriteLine(expr2.Simplify());
var expr3 = Arctan(Sin("a") / Cos("a"));
Console.WriteLine(expr3);
Console.WriteLine(expr3.Simplify());
var expr4 = Arccotan(Cos("a") / Sin("a"));
Console.WriteLine(expr4);
Console.WriteLine(expr4.Simplify());
var expr5 = Arcsec(Sec("aa")) + Arccosec(Cosec("bb"));
Console.WriteLine(expr5);
Console.WriteLine(expr5.Simplify());

arcsin(x) + arccos(x)
arcsin(sin(x)) + arccos(cos(y))
x + y
arctan(sin(a) / cos(a))
a
arccotan(cos(a) / sin(a))
a
arcsec(sec(aa)) + arccsc(csc(bb))
aa + bb