题目内容
若tan(a+10°)=![](http://thumb.1010pic.com/pic6/res/czsx/web/STSource/20131101192119806561249/SYS201311011921198065612014_ST/0.png)
A.20°
B.30°
C.35°
D.50°
【答案】分析:根据特殊角的三角函数值计算即可.
解答:解:∵tan(a+10°)=
,而tan60°=
,
∴a+10°=60°,
∴a=50°.
故选D.
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:∵tan(a+10°)=
![](http://thumb.1010pic.com/pic6/res/czsx/web/STSource/20131101192119806561249/SYS201311011921198065612014_DA/0.png)
![](http://thumb.1010pic.com/pic6/res/czsx/web/STSource/20131101192119806561249/SYS201311011921198065612014_DA/1.png)
∴a+10°=60°,
∴a=50°.
故选D.
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°=
![](http://thumb.1010pic.com/pic6/res/czsx/web/STSource/20131101192119806561249/SYS201311011921198065612014_DA/2.png)
![](http://thumb.1010pic.com/pic6/res/czsx/web/STSource/20131101192119806561249/SYS201311011921198065612014_DA/3.png)
![](http://thumb.1010pic.com/pic6/res/czsx/web/STSource/20131101192119806561249/SYS201311011921198065612014_DA/4.png)
![](http://thumb.1010pic.com/pic6/res/czsx/web/STSource/20131101192119806561249/SYS201311011921198065612014_DA/5.png)
sin45°=
![](http://thumb.1010pic.com/pic6/res/czsx/web/STSource/20131101192119806561249/SYS201311011921198065612014_DA/6.png)
![](http://thumb.1010pic.com/pic6/res/czsx/web/STSource/20131101192119806561249/SYS201311011921198065612014_DA/7.png)
sin60°=
![](http://thumb.1010pic.com/pic6/res/czsx/web/STSource/20131101192119806561249/SYS201311011921198065612014_DA/8.png)
![](http://thumb.1010pic.com/pic6/res/czsx/web/STSource/20131101192119806561249/SYS201311011921198065612014_DA/9.png)
![](http://thumb.1010pic.com/pic6/res/czsx/web/STSource/20131101192119806561249/SYS201311011921198065612014_DA/10.png)
![](http://thumb.1010pic.com/pic6/res/czsx/web/STSource/20131101192119806561249/SYS201311011921198065612014_DA/11.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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若tan(a+10°)=
,则锐角a的度数是( )
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