![](https://static.youtibao.com/asksite/comm/h5/images/m_q_title.png)
[单选题]
如图,D,E,F△ABC的边AB,BC,AC的中点,若△ABC的面积为16,则三角形△DEF的面积是()
A.16
B.12
C.8
D.4
![](https://static.youtibao.com/asksite/comm/h5/images/m_q_a.png)
D、4
![](https://static.youtibao.com/asksite/comm/h5/images/solist_ts.png)
A.16
B.12
C.8
D.4
D、4
A.30°
B.40°
C.50°
D.60°
A.∠BCB′=∠ACA′
B.∠ACB=2∠B
C.∠B′CA=∠B′AC
D.′C平分∠BB′A′
A.2
B.3
C.4
D.5
个简支边上受均布力矩M,在两个自由边上受均布力矩μM。试证w=f(x)能满足一切条件,并求出挠度,弯矩和反力