Can someone please help me?

Find the exact value by using a half-angle identity. sin(7pi/8)

its a practice question and im so confused.

Question

Can someone please help me? 

Find the exact value by using a half-angle identity. sin(7pi/8) 

its a practice question and im so confused.

firejay5 · Answer

sin(7pi/8) = +_ ( sqrt( 1- cos(14pu/8)/2) 

= sqrt ( (1- cos7pi/4)/2 ) 

= sqrt ( 1-sqrt(3)/2 )/2 ) 

=sqrt (2 -sqrt(3))/2

It depends on the angel and assumption that you will take positive or negative

anonymous · Answer

@Firejay5 ...you literally just copied and pasted that from yahoo answers.
i was hoping for an explanation but
ok?????

anonymous · Answer

https://answers.yahoo.com/question/index?qid=20100427104813AAE0Lvs

firejay5 · Answer

Well dude/girl did you want help you or not, that was up to you