问题
填空题
sin45°cos15°+cos225°•sin15°的值为______.
答案
∵sin45°cos15°+cos225°•sin15°
=
cos15°-2 2
sin15°2 2
=cos(45°+15°)
=
.1 2
故答案为:
.1 2
sin45°cos15°+cos225°•sin15°的值为______.
∵sin45°cos15°+cos225°•sin15°
=
cos15°-2 2
sin15°2 2
=cos(45°+15°)
=
.1 2
故答案为:
.1 2