C4a : Trigonometric, inverse trigonometric

F06BCF	Recover cosine and sine from given real tangent
F06CCF	Recover cosine and sine from given complex tangent, real cosine
F06CDF	Recover cosine and sine from given complex tangent, real sine
S07AAF	$\tan x$
S09AAF	$\arcsin x$
S09ABF	$\arccos x$