立体几何(急·~~怎么做的过程写出,还有画图)1.在正方体ABCD-A1B1C1D1中,E1在A1B1上,F1在C1D1上,且B1E1=D1F1=(A1B1)/4,则BE1与DF1所成角余弦值(15/17)2.在长方体ABCD-A1B1C1D1中,如果AB=BC=a,AA1=2a,那么
来源:学生作业帮助网 编辑:作业帮 时间:2024/07/18 00:03:42
![立体几何(急·~~怎么做的过程写出,还有画图)1.在正方体ABCD-A1B1C1D1中,E1在A1B1上,F1在C1D1上,且B1E1=D1F1=(A1B1)/4,则BE1与DF1所成角余弦值(15/17)2.在长方体ABCD-A1B1C1D1中,如果AB=BC=a,AA1=2a,那么](/uploads/image/z/9585200-56-0.jpg?t=%E7%AB%8B%E4%BD%93%E5%87%A0%E4%BD%95%EF%BC%88%E6%80%A5%C2%B7%EF%BD%9E%EF%BD%9E%E6%80%8E%E4%B9%88%E5%81%9A%E7%9A%84%E8%BF%87%E7%A8%8B%E5%86%99%E5%87%BA%2C%E8%BF%98%E6%9C%89%E7%94%BB%E5%9B%BE%EF%BC%891.%E5%9C%A8%E6%AD%A3%E6%96%B9%E4%BD%93ABCD-A1B1C1D1%E4%B8%AD%2CE1%E5%9C%A8A1B1%E4%B8%8A%2CF1%E5%9C%A8C1D1%E4%B8%8A%2C%E4%B8%94B1E1%3DD1F1%3D%EF%BC%88A1B1%EF%BC%89%2F4%2C%E5%88%99BE1%E4%B8%8EDF1%E6%89%80%E6%88%90%E8%A7%92%E4%BD%99%E5%BC%A6%E5%80%BC%EF%BC%8815%2F17%EF%BC%892.%E5%9C%A8%E9%95%BF%E6%96%B9%E4%BD%93ABCD-A1B1C1D1%E4%B8%AD%2C%E5%A6%82%E6%9E%9CAB%3DBC%3Da%2CAA1%3D2a%2C%E9%82%A3%E4%B9%88)
xWkOW+n83>cc̖4DU[6%JdH|!$!I iÒHΙ/yC&vm%9{:o07lQo,sFjG
350k>Â>gk|yTc_b<2+ФCs30lӂ^D\w|EfQ6 AsJ0ps)#wھ7Vx1O!e6 Ylb?56ֵ11U[P濙ہ_sssY=X=o>;szuWU썵m;yANm5;!ݙr U"g|U츌<@C8d=kv\Gƣ]hU=s_^x@!C4믖}UvXSCō:Q=[5oexpUe$Me|S<&]Cj'܃YɁQ"H F#L8]45BOW0vm⒳)OYQPB",mOܩD `
xz*8af`jSf[lmbs^+; 9`EWVq
)@Pz[/QFAH R xa>56fqWb Ij`=5?a9--"N@;;B~huuj8Etc+|@LⶌgA=k=, ʘKWzf/7 +S4>15>yerZ&_ߍO$c{~c%x//?0S?HX|t0&{F
>wp 1/J