3.3.2¡¡º¯ÊýµÄ¼«ÖµÓëµ¼Êý

Ë«»ù´ï±ê¡¡£¨ÏÞʱ20·ÖÖÓ£©

1£®ÏÂÁк¯Êý´æÔÚ¼«ÖµµÄÊÇ(¡¡¡¡)£®

A£®y£½                                                               B£®y£½x£­e^x

C£®y£½x³£«x²£«2x£­3                                            D£®y£½x³

½âÎö¡¡AÖÐf′(x)£½£­£¬Áîf′(x)£½0Î޽⣬ÇÒf(x)Ϊ˫Çúº¯Êý£¬∴AÖк¯ÊýÎÞ¼«Öµ£®BÖÐf′(x)£½1£­e^x£¬Áîf′(x)£½0¿ÉµÃx£½0.µ±x<0ʱ£¬f′(x)>0£»µ±x>0ʱ£¬f′(x)<0.∴y£½f(x)ÔÚx£½0´¦È¡¼«´óÖµ£¬f(0)£½£­1.CÖÐf′(x)£½3x²£«2x£«2£¬Δ£½4£­24£½£­20<0.∴y£½f(x)ÎÞ¼«Öµ£¬DÒ²ÎÞ¼«Öµ£®¹ÊÑ¡B.

´ð°¸¡¡B

2£®º¯Êýy£½1£«3x£­x³ÓÐ(¡¡¡¡)£®

A£®¼«Ð¡Öµ£­1£¬¼«´óÖµ1                                     B£®¼«Ð¡Öµ£­2£¬¼«´óÖµ3

C£®¼«Ð¡Öµ£­2£¬¼«´óÖµ2                                      D£®¼«Ð¡Öµ£­1£¬¼«´óÖµ3