Как найти тангенс пи/12?

when x/2=pi/12 x=2 (pi/12)=pi/6 so when tan (x/2)=sinx / (1+cosx) so tan (pi/12)=sin (pi/6) / [1+cos (pi/6) ] now substitute sin (pi/6)=1/2 and cos (pi/6)=√3/2 tan (pi/12)=(1/2) / (1+√3/2)=(1/) / (2+√3) now rationalize the denominator by multiplying with (2 — √3) / (2 -√3) tan (pi/12)=(2 — √3) / (2+√3) (2 — √3) tan (pi/12)=(2 — √3) / (4 — 3)=(2 — √3)