sin -15 = ? (Rumus jumlah dan selisih)

sin -15 ° = -sin ( 45° - 30°)
= -sin 45 cos 30 - cos 45 sin 30
= -1/2√2 1/2√3 - 1/2√2 1/2
= -1/4√6 - 1/4√2
= -1/4( √6 - √2)




^_^