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计算sin2150°+sin2135°+2sin210°+cos2225°的值是()A.14B.34C.114D.94

题目详情
计算sin2150°+sin2135°+2sin210°+cos2225°的值是(  )
A.
1
4

B.
3
4

C.
11
4

D.
9
4
▼优质解答
答案和解析
sin2150°+sin2135°+2sin210°+cos2225°=sin230°+sin245°-2sin30°+cos245°
=
1
4
+
1
2
-1+
1
2
=
1
4

故选:A.