Answer:
2 - sqrt(3)
Step-by-step explanation:
Split pi/12 into two angles where the values of the six trigonometric functions are known.
tan (pi/4 - pi/6)
Apply the difference of angles identity
![\frac{tan(pi/4) - tan(pi/6)}{1 + tan(pi/4)tan(pi/6)}](https://tex.z-dn.net/?f=%5Cfrac%7Btan%28pi%2F4%29%20-%20tan%28pi%2F6%29%7D%7B1%20%2B%20tan%28pi%2F4%29tan%28pi%2F6%29%7D)
tan(pi/4) = 1 , tan(pi/6) = (sqroot3)/3
Plug in and Simplify
![\frac{1-\frac{\sqrt{3} }{3} }{1+1\frac{\sqrt{3} }{3} }](https://tex.z-dn.net/?f=%5Cfrac%7B1-%5Cfrac%7B%5Csqrt%7B3%7D%20%7D%7B3%7D%20%7D%7B1%2B1%5Cfrac%7B%5Csqrt%7B3%7D%20%7D%7B3%7D%20%7D)
![\frac{\frac{3-\sqrt{3} }{3} }{\frac{3+\sqrt{3} }{3} }](https://tex.z-dn.net/?f=%5Cfrac%7B%5Cfrac%7B3-%5Csqrt%7B3%7D%20%7D%7B3%7D%20%7D%7B%5Cfrac%7B3%2B%5Csqrt%7B3%7D%20%7D%7B3%7D%20%7D)
![\frac{3-\sqrt{3} }{3} *\frac{3}{3+\sqrt{3} }](https://tex.z-dn.net/?f=%5Cfrac%7B3-%5Csqrt%7B3%7D%20%7D%7B3%7D%20%2A%5Cfrac%7B3%7D%7B3%2B%5Csqrt%7B3%7D%20%7D)
Need to multiply this by ![\frac{3+\sqrt{3} }{3+\sqrt{3} }](https://tex.z-dn.net/?f=%5Cfrac%7B3%2B%5Csqrt%7B3%7D%20%7D%7B3%2B%5Csqrt%7B3%7D%20%7D)
Expand and simplify numerator: ![\frac{6}{(3+\sqrt{3} )^{2} }](https://tex.z-dn.net/?f=%5Cfrac%7B6%7D%7B%283%2B%5Csqrt%7B3%7D%20%29%5E%7B2%7D%20%7D)
Expand and simplify denominator: ![\frac{6}{12+6\sqrt{3}}](https://tex.z-dn.net/?f=%5Cfrac%7B6%7D%7B12%2B6%5Csqrt%7B3%7D%7D)
Cancel the common factor: ![\frac{1}{2+\sqrt{3}}](https://tex.z-dn.net/?f=%5Cfrac%7B1%7D%7B2%2B%5Csqrt%7B3%7D%7D)