问题 解答题
计算下列各题.
(1)sin230°+cos245°+
2
sin60°•tan45°;
(2)
cos230°+cos260°
tan60°•cot30°
+tan60°;
(3)tan2°tan4°•tan6°…tan88°.
答案

(1)原式=(

1
2
2+(
2
2
2+
2
×
3
2
×1,

=

1
4
+
1
2
+
6
2

=

3
4
+
6
2

(2)原式=

(
3
2
)
2
+(
1
2
)
2
3
×
3
+
3

=

1
3
+
3

(3)原式=tan2°•tan4°•tan6°•cot6°•cot4°•cot2°,

=(tan2°•cot2°)(tan4°•cot4°)•(tan6°•cot6°),

=1

单项选择题 A1/A2型题
单项选择题