Вычислите sin 1650градусов. и cos(-1650)градусов !

1650/360 = 4,58...
360*4 = 1440
1650 - 1440 = 210
sin 210 = -1/2
cos -210 = cos 150 = -√3/2

Sin(1650°) = sin( 4*360°+210°) = sin(210°) = sin(180°+30°) = -sin(30°) =
= -0,5.
cos(-1650°) = cos(1650°) = cos(4*360°+210°) = cos(210°) =
= cos(180° + 30°) = - cos(30°) = -(√3)/2