1.

Prove that `tan(pi/12) . tan(5 pi/12) . tan(7pi/12) . tan(11pi/12) =1`

Answer» `tan5/12pi=cot(pi/2-5/12pi)=cotpi/12`
`tan7/12pi=tan(pi-7/12pi)=-tan5/12pi=-cotpi/12`
`tan7/12pi=-tanpi/12`
`tanpi/12*cotpi/12-cotpi/12*-tanpi/12`
1.


Discussion

No Comment Found