Returns the tangent of the given value, in radians
Implemented by: dartmouth4, hptsb, decbasic, altair8K, Applesoft, TI994, CBM, msatari, level2, colormc, colorext, zx81, spectrum, BBC, GWBASIC, MSX, bwbasic, bw32, ABasiC, QBasic, VBDOS, FreeBASIC, Gambas, minibasicmm, minibasicjs, EndBASIC
With variations:
Also written as: