题目内容
计算:(1)
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(2)6tan230°-
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【答案】分析:根据特殊角的三角函数值计算.
解答:解:(1)把cos30°=
,sin45°=
,代入得:原式=
×
+
×
=
;
(2)tan30°=
,sin60°=
,sin45°=
代入得:原式=6×
-
×
-2×
=
-
.
点评:本题考查特殊角三角函数值的计算,特殊角三角函数值计算在中考中经常出现,题型以选择题、填空题为主.
【相关链接】特殊角三角函数值:
sin30°=
,cos30°=
,tan30°=
,cot30°=
;
sin45°=
,cos45°=
,tan45°=1,cot45°=1;
sin60°=
,cos60°=
,tan60°=
,cot60°=
.
解答:解:(1)把cos30°=
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(2)tan30°=
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点评:本题考查特殊角三角函数值的计算,特殊角三角函数值计算在中考中经常出现,题型以选择题、填空题为主.
【相关链接】特殊角三角函数值:
sin30°=
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sin45°=
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sin60°=
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