ÌâÄ¿ÄÚÈÝ

3£®ÒÑÖªº¯Êýf£¨x£©=£¨2k-1£©lnx+$\frac{k}{x}$+2x£¬ÓÐÒÔÏÂÃüÌ⣺
¢Ùµ±k=-$\frac{1}{2}$ʱ£¬º¯Êýf£¨x£©ÔÚ£¨0£¬$\frac{1}{2}}$£©Éϵ¥µ÷µÝÔö£»
¢Úµ±k¡Ý0ʱ£¬º¯Êýf£¨x£©ÔÚ£¨0£¬+¡Þ£©ÉÏÓм«´óÖµ£»
¢Ûµ±-$\frac{1}{2}$£¼k£¼0ʱ£¬º¯Êýf£¨x£©ÔÚ£¨$\frac{1}{2}$£¬+¡Þ£©Éϵ¥µ÷µÝ¼õ£»
¢Üµ±k£¼-$\frac{1}{2}$ʱ£¬º¯Êýf£¨x£©ÔÚ£¨0£¬+¡Þ£©ÉÏÓм«´óÖµf£¨${\frac{1}{2}}$£©£¬Óм«Ð¡Öµf£¨-k£©£®
ÆäÖв»ÕýÈ·ÃüÌâµÄÐòºÅÊÇ£¨¡¡¡¡£©
A£®¢Ù¢ÛB£®¢Ú¢ÛC£®¢Ù¢ÜD£®¢Ú¢Ü

·ÖÎö Çóº¯ÊýµÄµ¼Êý£¬·Ö±ðÀûÓú¯Êýµ¥µ÷ÐԺ͵¼ÊýÖ®¼äµÄ¹ØÏµ½øÐÐÅжϼ´¿É£®

½â´ð ½â£ºº¯ÊýµÄ¶¨ÒåÓòΪ£¨0£¬+¡Þ£©£¬
º¯ÊýµÄµ¼Êýf¡ä£¨x£©=$\frac{2k-1}{x}$-$\frac{k}{{x}^{2}}$+2=$\frac{2{x}^{2}+£¨2k-1£©x-k}{{x}^{2}}$=$\frac{£¨x+k£©£¨2x-1£©}{{x}^{2}}$=$\frac{2£¨x+k£©£¨x-\frac{1}{2}£©}{{x}^{2}}$£¬
¢Ùµ±k=-$\frac{1}{2}$ʱ£¬f¡ä£¨x£©=$\frac{2£¨x-\frac{1}{2}£©^{2}}{{x}^{2}}$¡Ý0ºã³ÉÁ¢£¬Ôòº¯Êýf£¨x£©ÔÚ£¨0£¬+¡Þ£©Éϵ¥µ÷µÝÔö£¬
ÔòÔÚ£¨0£¬$\frac{1}{2}}$£©Éϵ¥µ÷µÝÔö£¬¹Ê¢ÙÕýÈ·£»
¢Úµ±k¡Ý0ʱ£¬ÓÉf¡ä£¨x£©£¾0µÃx£¾$\frac{1}{2}$£¬´Ëʱº¯ÊýΪÔöº¯Êý£¬
ÓÉf¡ä£¨x£©£¼0£¬µÃ0£¼x£¼$\frac{1}{2}$£¬´Ëʱº¯ÊýΪ¼õº¯Êý£¬¼´µ±x=$\frac{1}{2}$ʱ£¬º¯Êýf£¨x£©´æÔÚ¼«Ð¡Öµ£¬
¼´¿Éº¯Êýf£¨x£©ÔÚ£¨0£¬+¡Þ£©ÉÏÓм«´óÖµ´íÎ󣬹ʢڴíÎó£»
¢Ûµ±-$\frac{1}{2}$£¼k£¼0ʱ£¬Ôò0£¼-k£¼$\frac{1}{2}$£¬
ÓÉf¡ä£¨x£©£¼0µÃ-k£¼x£¼$\frac{1}{2}$£¬
ÓÉf¡ä£¨x£©£¾0µÃ0£¼x£¼-k»òx£¾$\frac{1}{2}$£¬¼´º¯Êýf£¨x£©ÔÚ£¨$\frac{1}{2}$£¬+¡Þ£©Éϵ¥µ÷µÝÔö£»¹Ê¢Û´íÎó£¬
¢Üµ±k£¼-$\frac{1}{2}$ʱ£¬-k£¾$\frac{1}{2}$£¬ÓÉf¡ä£¨x£©£¾0µÃ0£¼x£¼$\frac{1}{2}$»òx£¾-k£¬´Ëʱº¯Êýµ¥µ÷µÝÔö£¬
ÓÉf¡ä£¨x£©£¼0µÃ$\frac{1}{2}$£¼x£¼-k£¬¼´º¯ÊýΪ¼õº¯Êý£¬
¼´º¯Êýf£¨x£©ÔÚ£¨0£¬+¡Þ£©ÉÏÓм«´óÖµf£¨${\frac{1}{2}}$£©£¬Óм«Ð¡Öµf£¨-k£©£®¹Ê¢ÜÕýÈ·£¬
¹Ê²»ÕýÈ·ÃüÌâµÄÐòºÅ¢Ú¢Û£¬
¹ÊÑ¡£ºB

µãÆÀ ±¾ÌâÖ÷Òª¿¼²éÃüÌâµÄÕæ¼ÙÅжϣ¬Éæ¼°º¯ÊýµÄµ¥µ÷ÐԺ͵¼ÊýµÄ¹ØÏµ£¬¿¼²éѧÉúµÄ¼ÆËãÄÜÁ¦£®

Á·Ï°²áϵÁдð°¸
Ïà¹ØÌâÄ¿

Î¥·¨ºÍ²»Á¼ÐÅÏ¢¾Ù±¨µç»°£º027-86699610 ¾Ù±¨ÓÊÏ䣺58377363@163.com

¾«Ó¢¼Ò½ÌÍø