SOLUTION: True or false: sin(-85)=-sin85 Thank you so much for all of your help!!!! God Bless!!!!

Algebra ->  Trigonometry-basics -> SOLUTION: True or false: sin(-85)=-sin85 Thank you so much for all of your help!!!! God Bless!!!!      Log On


   

Question 389898: True or false: sin(-85)=-sin85
Thank you so much for all of your help!!!!
God Bless!!!!
Found 2 solutions by stanbon, josmiceli:
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
True or false: sin(-85)=-sin85
----------
True
----
In general sin(-x) = -sin(x)
======
Cheers,
Stan H.

Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
looks true to me
Looking at the right side, 85 degrees is in the 1st quadrant
between 0 and 90 degrees, and sin is (+)
Therefore -sin%2885%29 is (-)
--------------
Looking at the left side, -85 degrees is in the 4th quadrant
where the sin is (-)
so, the equation says
-.9962+=+-.9962