Arccos(-45)

• Real numbers: arccos is defined only for inputs in [-1, 1]. Since -45 is outside, there is no real value.

• Complex value (principal branch): arccos(-45) = pi - i arcosh(45) = pi - i ln(45 + sqrt(45^2 - 1)) = pi - i ln(45 + sqrt(2024)).

Numerically, arccos(-45) ≈ 3.14159265 - 4.49967600 i.