满分5 >
高中数学试题 >
若△ABC的三个内角满足sinA:sinB:sinC=5:11:13,则△ABC...
若△ABC的三个内角满足sinA:sinB:sinC=5:11:13,则△ABC( )
A.一定是锐角三角形
B.一定是直角三角形
C.一定是钝角三角形
D.可能是锐角三角形,也可能是钝角三角形
考点分析:
相关试题推荐
(上海卷理18)某人要制作一个三角形,要求它的三条高的长度分别为
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131023211942713107816/SYS201310232119427131078005_ST/0.png)
,则此人能( )
A.不能作出这样的三角形
B.作出一个锐角三角形
C.作出一个直角三角形
D.作出一个钝角三角形
查看答案
平面上O,A,B三点不共线,设
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131023211942713107816/SYS201310232119427131078004_ST/0.png)
,则△OAB的面积等于( )
A.
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131023211942713107816/SYS201310232119427131078004_ST/1.png)
B.
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131023211942713107816/SYS201310232119427131078004_ST/2.png)
C.
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131023211942713107816/SYS201310232119427131078004_ST/3.png)
D.
查看答案
E,F是等腰直角△ABC斜边AB上的三等分点,则tan∠ECF=( )
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131023211942713107816/SYS201310232119427131078003_ST/images0.png)
A.
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131023211942713107816/SYS201310232119427131078003_ST/0.png)
B.
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131023211942713107816/SYS201310232119427131078003_ST/1.png)
C.
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131023211942713107816/SYS201310232119427131078003_ST/2.png)
D.
查看答案
在△ABC中,角A,B,C所对的边长分别为a,b,c,若∠C=120°,c=
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131023211942713107816/SYS201310232119427131078002_ST/0.png)
a,则( )
A.a>b
B.a<b
C.a=b
D.a与b的大小关系不能确定
查看答案
在△ABC中,a=15,b=10,A=60°,则cosB=( )
A.-
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131023211942713107816/SYS201310232119427131078001_ST/0.png)
B.
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131023211942713107816/SYS201310232119427131078001_ST/1.png)
C.-
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131023211942713107816/SYS201310232119427131078001_ST/2.png)
D.
查看答案