Question

find the exact value of sin(3pi/8)
a) -√(2-√2)/2
b) √(2-√2)/2
c) - √(2+√2)/2
d) √(2+√2)/2

Answer 1

Hey to do this you would use the half angle formula

Answer 2

So we know sin (3pi/4) right?
use the formula \[\sin (\theta \div 2)=\sqrt{\frac{ 1-\cos2\theta }{ 2 }}\]

Answer 3

So theta would be 3pi/4. Plug it into the formula above and solve

Answer 4

and cos (6pi/4)=0. So we are left with \[\frac{ \sqrt{2} }{ 2 }\]

Answer 5

what answer choice would that be though?

Answer 6

one sec i will use a calculator

Answer 7

okay

Answer 8

Ok it would be D

Answer 9

Sorry for the slow answer a friend of mine has been stuck in an airport for the past 7 hrs

Answer 10

thank you so much!

Answer 11

Hey i see a mistake..Above i gave you the wrong formula for half angle it is really 1-cos (theta) in the sqrt. So you would get...\[\frac{ \sqrt{(1-\cos \theta)/2} }{ ? }\]

Answer 12

and it would become...\[\sqrt{1-\frac{ \sqrt{2} }{ 2 }}\]

Answer 13

and that boils down to...\[\sqrt{\frac{ 2-\sqrt{2} }{ 2 }}\]

Answer 14

Which is D.

Answer 15

I mean B lol

Answer 16

it was D though

Answer 17

yea it's D my bad..just double checked....anyway i g2g now