Question

Find the exact value of sin(11pi/8).

Choices are in the attachment.

Answer 1

sin ( 11π / 8 ) = sin ( π + 3 π/ 8 ) =
= - sin ( 3π/8 ) =
= - sin ( 3π/4 / 2 ) =

`=- \sqrt{ (1-cos(3 \pi /4))/(2) }= \\ =- \sqrt{ (1-(- √(2)/2 ))/(2) }= \\ = - \sqrt{ (2+ √(2) )/(4) }`
Answer: B ) is correct