cos15°-sin15°=?

来源：学生作业帮助网 编辑：作业帮 时间：2024/11/07 20:53:11

cos15°-sin15°=?
cos15°-sin15°=?

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

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

cos15°-sin15°=cos(15°+15°)=cos30°=√3/2

(sin15°－cos15°)/(sin15°+cos15°)= cos15°-sin15°=? sin15°cos15°= sin15°+cos15°= sin15°=?cos15°=? 计算：cos15°sin15°=? 2sin15°cos15°= ? 2sin15° cos15°= 化简sin15°-cos15°/sin15°+cos15° sin15°-cos15°/sin15°+cos15°的值? 化简sin15°-cos15°/sin15°+cos15° sin15°-cos15°/sin15°+cos15°的值? sin15°cos15°等于 sin15°+cos15°过程 sin15°cos15°等于? 化简：sin15°*cos15° sin15°cos15°是什么意思 sin15°cos75°+cos15°sin105°=?