I am having a brain freeze on this one. Solution would be great.
Prove:
sin330cos150 - cos390sin390 = 0
Thanks so much
Evaluate
$\displaystyle \sin(330)\cos(150) - \cos(390)\sin(390) $
If it is equal to zero then you have proved it.
I'll kick it off
$\displaystyle \sin(330)\cos(150) - \cos(390)\sin(390) $
$\displaystyle \sin(360-30)\cos(180-30) - \cos(360+30)\sin(360+30) $
$\displaystyle -\sin(30)\times -\cos(30) - \cos(30)\sin(30) $
you have it from here?