2020Äê±±¾©ÊÐͨÖÝÇøÊýѧһģÊÔ¾í¼°´ð°¸

?PS??33t?, 22EÊÇABÖе㣬AD//EF,AB=2, AD?EN?PE

PA?EN?2(t?1)

t?QN?2t?2(t?1) ¡­¡­.¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­(3·Ö)

t?S?DPQ?1(2t?2(t?1))(2t=

333t??) 2223233t?t? 2223233t?t?¡­¡­¡­¡­.¡­¡­.¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­(4·Ö) 222S?(3)¸ù¾ÝÌâÒâ¿ÉÖª£ºAM?1t, 2?DM?2?1t

2?DP2?(DM)2?(PM)2

13DP2?(2?t)2?(t)2

22DP2?t2?2t?4

¸ù¾Ý¹´¹É¶¨Àí¿ÉµÃ£ºDQ?(2321)?(2t?2?)2 22DQ2?(321)?(2t?2?)2?4t2?10t?7 22t?123(t?1)2)?() 22PQ2?QN2?PN2?(2t?PQ2?7t2?4t?1

¢Ù µ±?PDQ?90?

PQ2?DQ2?PD2

7t2?4t?1=4t2?10t?7+t2?2t?4

½âÖ®µÃ£ºt?6?1£¨ÉḺ£©¡­¡­.¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­(5·Ö)

222¢Ú µ±?DPQ?90?DQ?PQ?PD

4t2?10t?7=7t2?4t?1+t2?2t?4

½âÖ®µÃ£ºt?6?1£¨ÉḺ£©¡­¡­.¡­¡­.¡­¡­¡­¡­¡­¡­¡­¡­(6·Ö) 2222¢Û µ±?DQP?90?,PD?DQ?PQ

t2?2t?4=7t2?4t?1+4t2?10t?7

½âÖ®µÃ£ºt?4?6¡­¡­.¡­¡­.¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­(7·Ö) 54?66?1£¬t?6?1ʱ?DPQÊÇÖ±½ÇÈý½ÇÐÎ. £¬t?52×ÛÉÏ£¬µ±t?

[×¢]ѧÉúÕýÈ·´ð°¸Óë±¾´ð°¸²»Í¬£¬ÇëÀÏʦÃÇ×ÃÇé¸ø·Ö¡£