cos-1(0.73218673816

cos-1(0.73218673816)

There are two interpretations

1.\((a^{-1}=\frac{1}{a})\)

\(cos^{-1}(0.73218673816rad)=\frac{1}{cos(0.73218673816rad)}=1.34460226097\)

\(cos^{-1}(0.73218673816deg)=\frac{1}{cos(0.73218673816deg)}=1.00008165786\)

2. \( (Keys \ of \ the \ pocket \ calculator)\)

\(cos^{-1}(0.73218673816)=acos(0.73218673816)\)

\(=42.93deg =0.749269312889rad\)

Merry Christmas and a happy new year, asinus :- )   !