Question

What is the value of sin330? How to
Calculate without quadrant formula​

Answer 1

Answer:

$we \: know \: from \: trigonometry \: that \: \\ \sin(a - b) = \sin \: a \: . \: \cos \: b \: - \cos \: a \: . \: \sin \: b \: \\ \\ hence \\ sin330 = sin(330 - 30) = \sin330 \: . \: cos30 - cos330 \: . \: sin30 = 0 \: . \: \binom{ \sqrt{3} }{2} - 1 \: . \: \binom{1}{2 }= - \frac{1}{2}$