Đề kiểm tra giữa HKI môn toán lớp 11 - TP.HCM

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Câu 6 : 

           Cho hình chóp S.ABCD, có đáy là hình bình hành. Gọi M,N lần lượt là trung điểm của SA ,SD và K là điểm trên cạnh SB sao cho SK = 2KB.

            a/ Xác định :

- Giao tuyến (d1) của hai mặt phẳng (SBC) và (SAD).

                                - Giao tuyến (d2) của hai mặt phẳng (SBC) và (KMN).  

b/ Gọi J là giao điểm của d2 và SC. Tính tỉ số: S∆SNJ/S∆SDC

          c/ DM cắt mp(SBC) tại I .Tứ giác ISDA là hình gì?

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