Question

Using exact value symmetry I find that sin330 = +1/2... But shouldn't it be negative?

Answer 1

good, how did u get 1/2 ?

Answer 2

*facepalm*
Looking at the wrong question in my book, I mean sqrt3/2.

Answer 3

yes could you also show me how to get sqrt3/2 ? :)

Answer 4

Now you have me worried xD Well here is my working:
sin330 = sin(360-30)
=+sin30
sin = opp/hyp
Using the 30/60 degree triangle,
opp=sqrt3 and hyp=2

Which then leads me to believe that I was looking from the 60degree that I got sqrt3/2, but sin30 should be 1/2...

Answer 5

small mistake

Answer 6

since the period of `sin` is `360`, adding or subtracting 360 from angle will not change anything, so :

sin(330) = sin(360 - 30) = sin(-30) = -sin(30)