Texas Instruments TI-83 PLUS - Manual (Page 760)

TI-83 Plus General Information 757
Function Results
Function Range of Result
sin L 1 x , tan L 1 x L 90 ¡ to 90 ¡ or Lpà 2 to pà 2 (radians)
cos L 1 x 0 ¡ to 180 ¡ or 0 to p (radians)