You read it as arc sin ( sin (
I have now added some more clarifications at the end, to make all unambiguous.
If an inverse operator and the operator, or vice versa, are applied in succession on an operand a, the result is a.
Here, arc sin sin 5 = 5.
This return of 5 is independent of the unit used for measurement.
Also, if it is 5 radian =
By definition, the rule is both
The value entered as the operand is returned... . .