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在Rt△ABC中,∠C=90°,如果AB=2,BC=1,那么sinA的值是( )...
在Rt△ABC中,∠C=90°,如果AB=2,BC=1,那么sinA的值是( )
A.
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103101402571385700/SYS201311031014025713857006_ST/0.png)
B.
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103101402571385700/SYS201311031014025713857006_ST/1.png)
C.
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103101402571385700/SYS201311031014025713857006_ST/2.png)
D.
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103101402571385700/SYS201311031014025713857006_ST/3.png)
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如果∠α是等腰直角三角形的一个锐角,则tanα的值是( )
A.
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B.
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C.1
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在△ABC中,∠C=90°,∠B=2∠A,则cosA等于( )
A.
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103101402571385700/SYS201311031014025713857004_ST/0.png)
B.
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C.
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D.
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已知sinA=
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103101402571385700/SYS201311031014025713857003_ST/0.png)
,且∠A为锐角,则∠A=( )
A.30°
B.45°
C.60°
D.75°
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sin45°+cos45°的值等于( )
A.
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103101402571385700/SYS201311031014025713857002_ST/0.png)
B.
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103101402571385700/SYS201311031014025713857002_ST/1.png)
C.
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D.1
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计算:cos
245°+tan60°•cos30°等于( )
A.1
B.
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103101402571385700/SYS201311031014025713857001_ST/0.png)
C.2
D.
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