cos15°=cos(45°-30°) =cos45°cos30° + sin45°sin30°
=(√2/2)*(√3/2) + (√2/2)*(1/2)
=(√6+√2)/4
sin15° =sin(45°-30°)
=sin45°cos30° - cos45°sin30°
= (√2/2)*(√3/2) - (√2/2)*(1/2)
=(√6-√2)/4
cos15°=cos(45°-30°) =cos45°cos30° + sin45°sin30°
=(√2/2)*(√3/2) + (√2/2)*(1/2)
=(√6+√2)/4
sin15° =sin(45°-30°)
=sin45°cos30° - cos45°sin30°
= (√2/2)*(√3/2) - (√2/2)*(1/2)
=(√6-√2)/4