Question

cos(Cos^-1(5/8)) in radians? I got 5/8, can someone please confirm my answer?

Answer 1

Correct. To be more general, always check the domain for acos (arccos, cos^-1). In this case 5/8 is in the domain so the cos(acos(5/8)) simply cancel to give 5/8.

Answer 2

Thanks man!

Answer 3

They may throw you a screwball and say cos(cos^-1(2)), in which case you would have to say that this is not solve-able since 2 is outside of the domain of cos^-1

Answer 4

Ok, thanks for the tip