Question

Вычислить Sin 15 градусов

Answer 1

$sin15=sin(45-30)=sin45*cos30-cos45*sin30=\\=frac{sqrt{2}}{2}*frac{sqrt{3}}{2}-frac{sqrt{2}}{2}*frac{1}{2}=frac{sqrt{6}}{4}-frac{sqrt{2}}{4}=frac{sqrt{2}(sqrt{3}-1)}{4}$