如图1是一个用铁丝围成的篮框,我们来仿制一个类似的柱体形篮框.如图2,它是由一个半径为r、圆心角90°的扇形A
2OB
2 , 矩形A
2C
2EO、B
2D
2EO,及若干个缺一边的矩形状框A
1C
1D
1B
1、A
2C
2D
2B
2、…、A
nB
nC
nD
n , OEFG围成,其中A
1、G、B
1在
![](http://math.21cnjy.com/mml2svg?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmrow%3E%3Cmover+accent%3D%22true%22%3E%3Cmrow%3E%3Cmsub%3E%3Cmi%3EA%3C%2Fmi%3E%3Cmn%3E2%3C%2Fmn%3E%3C%2Fmsub%3E%3Cmsub%3E%3Cmi%3EB%3C%2Fmi%3E%3Cmn%3E2%3C%2Fmn%3E%3C%2Fmsub%3E%3C%2Fmrow%3E%3Cmo+stretchy%3D%22true%22%3E%E2%8C%A2%3C%2Fmo%3E%3C%2Fmover%3E%3C%2Fmrow%3E%3C%2Fmath%3E)
上,A
2、A
3…、A
n与B
2、B
3、…B
n分别在半径OA
2和OB
2上,C
2、C
3、…、C
n和D
2、D
3…D
n分别在EC
2和ED
2上,EF⊥C
2D
2于H
2 , C
1D
1⊥EF于H
1 , FH
1=H
1H
2=d,C
1D
1、C
2D
2、C
3D
3、C
nD
n依次等距离平行排放(最后一个矩形状框的边C
nD
n与点E间的距离应不超过d),A
1C
1∥A
2C
2∥A
3C
3∥…∥A
nC
n.