8.Èô £¨ £© £¨A£©54 £¨B£© 12 C£© 27 £¨D£© 72 9£®Èç¹ûº¯Êýf(x)£½2cos(2x£«¦Õ)(0<¦Õ<¦Ð)µÄͼÏóÏòÓÒƽÒƦÐ6ºó¹ØÓڵ㠳ÉÖÐÐĶԳƣ¬Ôòf(x)ÔÚÇø¼ä[0£¬¦Ð2]ÉϵÄÖµÓòΪ(¡¡¡¡) £¨A£©[-2, ] £¨B£© [- , ] £¨C£© [-2,1] £¨D£© [-2,2] 10.¶Ô ºã³ÉÁ¢µÄ³äÒªÌõ¼þÊÇ£¨ £© £¨A£© £¨B£© £¨C£© £¨D£© 11.ÔÚ¡÷ABCÖУ¬½ÇAΪ £¬½ÇAµÄƽ·ÖÏßAD½»BCÓÚµãD£¬ÒÑÖª ,ÇÒ ,Ôò ÔÚ ·½ÏòÉϵÄͶӰÊÇ£¨ £© £¨A£©1 £¨B£© £¨C£© 3 £¨D£© 12. É躯Êý £¬Èô´æÔÚ µÄ¼«Öµµã Âú×ã £¬Ôò µÄÈ¡Öµ·¶Î§ÊÇ£¨ £© £¨A£© £¨B£© £¨C£© £¨D£© ¶þ¡¢Ìî¿ÕÌ⣺±¾Ìâ¹²4СÌ⣬ÿСÌâ5·Ö£¬¹²20·Ö¡£ 13£®ÈôƽÃ浥λÏòÁ¿ Âú×ã £¬ÔòÏòÁ¿ µÄ¼Ð½ÇΪ _________£® 14. Éè±äÁ¿ Âú×ãÔ¼ÊøÌõ¼þ £¬ÔòÄ¿±êº¯Êý µÄ×îСֵΪ___________