??£1 ÒòΪf(t£«3)<0£½f(0)£¬ËùÒÔ? ?t£«3>0£¬? ½âµÃ£3 »¯¼òµÃlog4£x£½£2kx£¬ 4£«1 1 ¼´x£½£2kx¶ÔÒ»ÇÐx¡ÊRºã³ÉÁ¢£¬¡àk£½£2. (2)º¯Êýf(x)Óëg(x)µÄͼÏóÓÐÇÒÖ»ÓÐÒ»¸ö¹«¹²µã£¬ 1 ¼´·½³Ìlog4(4£«1)£2x£½log4(a¡¤2x£«a)ÓÐÇÒÖ»ÓÐÒ»¸öʵ¸ù£¬ x 1 »¯¼òµÃ·½³Ì2£«2x£½a¡¤2x£«aÓÐÇÒÖ»ÓÐÒ»¸öʵ¸ù£¬ÇÒa¡¤2x£«a>0³ÉÁ¢£¬ x Ôòa>0. Áît£½2x>0£¬Ôò(a£1)t2£«at£1£½0ÓÐÇÒÖ»ÓÐÒ»¸öÕý¸ù£® Éèg(t)£½(a£1)t2£«at£1£¬×¢Òâµ½g(0)£½£1<0£¬ËùÒÔ ¢Ùµ±a£½1ʱ£¬ÓÐt£½1£¬·ûºÏÌâÒ⣻