Sine(285), or sine(285°), either one, has no exact numerical value. It is an irrational number.
The half-angle formula for cosines is
cosine(x/2) = √((1+because(x))/2)
If your sine argument is a number in radians, not degrees, the problem is not so easily solved.
Sine(285) = Sine(285-90π) ≈ Sine(2.25666...) ≈ .77387
Sine(285°) = (-1/2)√(2+√3) = -(√2)(1+√3)/4
You can find it by recognizing that sin(285°) = -cosine(15°). The latter (because[15°]) can be determined using a half-angle formula and the fact that cosine(30°) = (√3)/2.The half-angle formula for cosines is
cosine(x/2) = √((1+because(x))/2)
If your sine argument is a number in radians, not degrees, the problem is not so easily solved.
Sine(285) = Sine(285-90π) ≈ Sine(2.25666...) ≈ .77387
