如图所示,正弦曲线y=sinx,余弦曲线y=cosx与两直线x=0,x=π所围成的阴影部分的面积为( )
A:1
B:2
C:2
D:2 2
如图所示,两条光线射向凸透镜,请在图中画出相应的折射光线。
-What were you doing at 8:00 last night ?
-Oh, I was busy _________ my homework