Find the sine value of (7pi)/6

Question

idku · Answer

7pi/6 = 210 degrees

sin(210)=sin(180+30)=sin(180)cos(30)+cos(180)sin(30)= ... can you finish it off ?

anonymous · Answer

kinda... can you walk me through? cause i'm having a hard time reading what you wrote.. sorry I'm blind lol

anonymous · Answer

7pi/6 is in quadran 3 right? and ur reference angle is pi/6 . therefore the value is -1/2 since sine in q3 is negative

anonymous · Answer

get it?

idku · Answer

:)

anonymous · Answer

okay that makes more sense. but how do you get there?

anonymous · Answer

Like I understand how you got the reference angle but how did you get -1/2?

nikato · Answer

Do you have a unit circle with you?

anonymous · Answer

yes

nikato · Answer

Ok. Look at the coordinate for 7pi/6

nikato · Answer

You see that it's 
( -sqrt3/2 , -1/2)

And when were finding sin, it's asking for the y-coordinate which is -1/2

nikato · Answer

And if they ask for cos, it'll be the x-coordinate

anonymous · Answer

that makes so much more sense!! thanks so much!!

nikato · Answer

No problem.
Glad you got it now

anonymous · Answer

glad u understand it :D took me a while to grasp trigonometry tooo.  and always sine is the  y axes and cosine is x axis just knowing that will come really handy in the future

anonymous · Answer

and now a plus to @nikato