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)