1 Answers
Sigma
·2012-02-10 09:40:25
just 2 steps :
take cos 3pi/7 to - cos4pi/7. now multiply 2 sin pi/7 to numertr and denomintr. the rest follows.
just 2 steps :
take cos 3pi/7 to - cos4pi/7. now multiply 2 sin pi/7 to numertr and denomintr. the rest follows.