hp 17bII+ cosine, tan trig functions

[Lonewolf]

Hello,
I just just keyed in the sine function I found from Gerson W. Barbosa in a 2006 posting:

SIN=L(SX:X*(5.8177641733
1E-3+L(X2Q(X))*(-3.281
8376137E-8+G(X2)*(5.5539
1606E-14+G(X2)*(2.0935E-
26*G(X2)-4.47566E-20))))
)*(3-4*SQ(G(SX)))

...and it works just fine... My question is, how do I key in these two simple identities in the solver function as an equation:

cos x = sin(90 - x)
tan x = sinx / cosx

I am not a programmer; any help would be appreciated.
/Silicon Valley Regards