const std = @import("../../std.zig");
const testing = std.testing;
const math = std.math;
const cmath = math.complex;
const Complex = cmath.Complex;
pub fn acos(z: anytype) Complex(@TypeOf(z.re)) {
const T = @TypeOf(z.re);
const q = cmath.asin(z);
return Complex(T).init(@as(T, math.pi) / 2 - q.re, -q.im);
}
const epsilon = 0.0001;
test "complex.cacos" {
const a = Complex(f32).init(5, 3);
const c = acos(a);
try testing.expect(math.approxEqAbs(f32, c.re, 0.546975, epsilon));
try testing.expect(math.approxEqAbs(f32, c.im, -2.452914, epsilon));
}