How to prove : tan(pi /12) = 1| / |4 + 1| / |-4 + 1| / |4 + ... + 1| / |-... + 1| / |... ?

[lvl107]

  Hello, Everyone.

  From :

  Thanks in advance.

[ttokoro · Accepted solution]

How about this?

[lvl107]

Many thanks for your time and help, ttokoro. 

    Regards.