计算下列各题:(1)sin230°+cos245°+2sin60°•tan45°;(2)12-4sin60°+(tan30°+1)0.

计算下列各题:(1)sin230°+cos245°+2sin60°•tan45°;(2)12-4sin60°+(tan30°+1)0.

题型:不详难度:来源:
计算下列各题:
(1)sin230°+cos245°+


2
sin60°•tan45°;
(2)


12
-4sin60°+(tan30°+1)0
答案
(1)原式=(
1
2
2+(


2
2
2+


2
×


3
2
×1
=
1
4
+
1
2
+


6
2

=
3
4
+
1
2


6


(2)原式=2


3
-4×


3
2
+1
=2


3
-2


3
+1
=1.
举一反三
sin30°+sin45°-
1
3
tan260°
题型:不详难度:| 查看答案
计算sin225°+2sin60°+tan45°-tan60°+cos225°的值.
题型:不详难度:| 查看答案
若4cos2α-1=0,则锐角α=______度.
题型:不详难度:| 查看答案
计算下列各题.
(1)sin230°+cos245°+


2
sin60°•tan45°;
(2)
cos230°+cos260°
tan60°•cot30°
+tan60°;
(3)tan2°tan4°•tan6°…tan88°.
题型:不详难度:| 查看答案
计算:
(1)(1-sin60°+cos60°)(sin90°+cos60°-cos30°);
(2)
cos45°-sin30°
cos45°+sin30°
-
cos40°
sin50°
题型:不详难度:| 查看答案
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