SIN COS TAN

Possible to do w/o calculator or not?

How do you think they were done before calculators?

use the taylor expansion.

tables
uber accurate graphs
and depending on angle addition/sum etc rules for trig involving known numbers ie sin cos tan 30-45-60...

emulation of a calculator on a logic gates-basis
abacus

use an infinate series.  calculate to number of decimal points desired.

sin(x) = sum as n goes from zero to infinity
((-1)^n)(x^(n+1))
-----------------
(2n+1)!

= (x)-((x^3)/3!)+((x^5)/5!)-((x^7)/7!)+...

and cos(x) = sum as n goes from zero to infinity

((-1)^n)(x^(2n))
----------------
(2n!)

won't write out the expansion of that one, though.  and it should be easy to see that you can get tan(x) from the two other equations.

You can use tailor series, incredibly accurate trig tables, or depending on the radian/degree, you can do it in your head.
For example, cosine of pi/2 radians = sqrt(2)/2 (after your rationalize the denominator)

I'm sorry. I posted the above thing, and it should be pi/4 radians, not pi/2 radians.