What is the difference between Cos(1/2)= and arcCos(1/2)=, why are they both equal to pi/3

Answer 1

in Cos(1/2) you are asking for the cosine of the angle which is 1/2 radian
using my calculator, I got .87758....

in arcCos(1/2) , you are asking for an angle whose cosine is 1/2
in degrees that would be 60° or π/3 in radians

They are NOT the same

Answer 2

however, cos^-1(1/2) is just another way to write arccos(1/2)