【正文】 ???ā??毿?娢???（III）求?N?灑葥v??????（1）求函數(shù) EMBED 
的值域；???????灑?????????焀甀愀琀椀漀渀?????ā?萀v???上最小值；???????灑?????????焀甀愀琀椀漀渀?????ā?萀????[解析]（1）令??????????????焀甀愀琀椀漀渀?????ā??（2）原函數(shù)等價(jià)于??????????焀甀愀琀椀漀渀?????ā??＊∵x∈R?? EMBED 
?????????????焀甀愀琀椀漀渀?????ā??瓿?刢??＊??????????????焀甀愀琀椀漀渀?????ā??若y≠1?????秿?????＊4(y????攀〢?????????焀甀愀琀椀漀渀?????ā??????????焀甀愀琀椀漀渀?????ā?攙礢?????礀攙??＊?禂???＊?jiǎng)tt=0????＊∴函數(shù)值域?yàn)閧y| EMBED 
≤y≤3}.?????嬀?邋嵧?謀????????灑????蒍???恾?＊也是學(xué)習(xí)三角的重要基本功?鏗齞?豾?k筎頊蒘?????【例4】 設(shè)0≤θ≤π?替????猀椀渀?挀漀猀????最????挀漀猀?猀椀渀???暫???萀v???0?????慦ā戰(zhàn)?＊g(θ)的最大值、最小值分別為c、d??試比較a、b、c、d的大小.?嬀邉嵧??〢攙?搃?????＊ EMBED 
??攙撟漀猀?搃ㄢ??????????焀甀愀琀椀漀渀?????ā???耊在（??????????焀甀愀琀椀漀渀?????ā???????????焀甀愀琀椀漀渀?????ā??藿祑?猀椀渀碭唀??麐?＊???＊sin1≤sin(cosθ) ≤sin1, ∴a=sin1, b=?珿椀渀????∵0≤sinθ≤1 EMBED 
,??字　???????????焀甀愀琀椀漀渀?????ā??????????焀甀愀琀椀漀渀?????ā?蔀祑?挀漀猀碭唀????＊??撟漀猀?攙撟漀猀?猀椀渀???攙ㄢ?猀捓???＊d=cos1。??碭??挀漀猀?碭萀v?捜桫杔是 ???＊函數(shù)y=sin EMBED 
+cos EMBED 
在（????＊2π）內(nèi)的單調(diào)遞減區(qū)間是 ???＊函數(shù)f(x)=cos（x+2θ）+sin(x???????灑?＊?jiǎng)tθ= ??　?＊已知a EMBED 
,則f(x)=(sinx+a)(cosx+a)的最小值為 ???咉須??????＊已知函數(shù) EMBED 
????????晬?碭?萀駛????（2）判斷f(x)的奇偶性；???????峿??灑晥?碭????宕?＊ EMBED 
??????????焀甀愀琀椀漀渀?????ā?崀?上的圖象；?????????灑葥啶?????12??聓??????????焀甀愀琀椀漀渀?????ā??13???上述函數(shù)的最小正周??（1）y=cotx?瓿愀渀碭?????????????????秿???＊8cos2x +8cos4x.????＊已知 EMBED 
的值.????＊設(shè)函數(shù)：??????????焀甀愀琀椀漀渀?????ā?萀v?捜桫杔為π??華晟?碭?萀駛????????????焀甀愀琀椀漀渀?????ā???＊值域?yàn)閇???＊10]??慬ā戰(zhàn)萀?????《答案?邉?《??一、1??????＊B 3??????＊A 5??????＊B ?諛???＊π 8?壽?＊ EMBED 
2π]?????＊ EMBED 
 10??????????焀甀愀琀椀漀渀?????ā???11??????????焀甀愀琀椀漀渀?????ā??（1）∵cosx≠0??騢???筎碭?簀碭懷歡???????????焀甀愀琀椀漀渀?????ā??毿?娢?緿???????????昢??＊x)= EMBED 
=?替?碭??＊∴f(x)為奇函數(shù)；?????????????????????嗿??麐?????欀??＊ EMBED 
,2kπ+ EMBED 
）；單調(diào)遞減區(qū)間是（2kπ+ EMBED 
??欀???????????焀甀愀琀椀漀渀?????ā???毿?娢???12?????????????焀甀愀琀椀漀渀?????ā??13?????????????焀甀愀琀椀漀渀?????ā??∵原函數(shù)的定義域是 EMBED 
即 EMBED 
（k∈Z）???灑葥駛??W??＊??鼢?灑葥v?捜桫杔T= EMBED 
.????????????????焀甀愀琀椀漀渀?????ā??（x∈R）???灑葥v?捜桫杔T= EMBED 
.????＊①當(dāng)n=2k(k∈Z)時(shí)??????????焀甀愀琀椀漀渀?????ā??②當(dāng)n=2k+1（k∈Z）時(shí)?? EMBED 
????＊?????????????焀甀愀琀椀漀渀?????ā??綜??＊a=2, b=0或a=???戀?????PAGE ????倀????????????????????倀?爀甀猀梔???ā???????????倀?爀甀猀梔???ā???????????倀?爀甀猀梔???ā?????