hitunglah nilai dari 2 sin 7,5 derajat cos 37,5 derajat

2sin7,5°cos37,5°
= 2cos37,5°sin7,5°
= sin75° - sin15°

sin75° = sin(45°+30°)
= sin45°cos30° + sin30°cos45°
= (½√2)(½√3) + (½)(½√2)
= ¼√6 + ¼√2 (*)

sin15° = sin(45°-30°)
= sin45°cos30° - sin30°cos45°
= (½√2)(½√3) - (½)(½√2)
= ¼√6 - ¼√2 (**)

sin75° - sin15°
=¼√6 + ¼√2 - (¼√6 - ¼√2)
=½√2