sin45°cos15°+cos225°•sin15°的值为1212．

Question

sin45°cos15°+cos225°•sin15°的值为

(1)/(2)

(1)/(2)

．

(1)/(2)

(1)/(2)(1)/(2)1122

(1)/(2)

(1)/(2)(1)/(2)1122

Answer 1

∵sin45°cos15°+cos225°•sin15°
=(√(2))/(2)cos15°-(√(2))/(2)sin15°
=cos（45°+15°）
=(1)/(2)．
故答案为：(1)/(2)． (√(2))/(2)√(2)√(2)√(2)

2

22222cos15°-(√(2))/(2)sin15°
=cos（45°+15°）
=(1)/(2)．
故答案为：(1)/(2)． (√(2))/(2)√(2)√(2)√(2)

2

22222sin15°
=cos（45°+15°）
=(1)/(2)．
故答案为：(1)/(2)． (1)/(2)111222．
故答案为：(1)/(2)． (1)/(2)111222．