【正文】
,1)2()41(104)13(03B4)1(41A142222????????????????????????xyxyxxyxxxyaaxay???),)或(,坐標(biāo)為(存在合適的點(diǎn),解得則的圖象上在點(diǎn)又即同底,且與解得得令),(的頂點(diǎn)為拋物線解析式為)、解:(5254P2,454)1(,544)1(P5544545S45S)2()0,3(),0,1(1,304)1(04)1(41M)(152122M A BP A B21222?????????????????????????????????????????????xxxyyxyyyyM A BP A BBAxxxyxykmxyPPPMP??? 二次函數(shù) )0(2 ???? acbxaxy 的圖象和性質(zhì) 一、理解新知 直線 abx 2?? ( a bacab 4422?? ,) 頂 ab2? abac442? y 軸 向上 低 ab2?? ab2?? ;向下 高 ab2?? ab2?? 二、知識(shí)鞏固練習(xí): (一)選擇: B C D D B B D B (二)填空: 下 x=1 ( 1, 1) 1 90 6 21?x 1 ( 4, 3) 123 yyy ?? 322 ???? xxy ④ (三)解答: 2522125221052542212 ??????????????????????????????xxycbacbacbaab則拋物線的解析式為解得、解:由已知得 8244S03B01A3,1032041D43211D)2(32323121),3,0()3,2(12A B D2122??????????????????????????????????????),(),(即解得得令),(即拋物線的頂點(diǎn)為點(diǎn)則拋物線的解析式為解得則線則拋物線的對(duì)稱軸為直、)由已知得、解:(xxxxyyxxxycbcbxCEDD? ),(即解得即得由得由),(即得令解得得令時(shí),當(dāng)解得上)在拋物線,(點(diǎn))、解:(32D2,0332303||SS30C,3,0)3()0,1(1,3,0320323)2(3069203A13212A B CA B D21222???????????????????????????????????????? xxxxyyyyyxBxxxxyxxymmmmxxyC?),(得令對(duì)稱軸為解得則設(shè)),(即得代入令與對(duì)稱軸的交點(diǎn)為點(diǎn)最小最小,則最小,則使若使的長(zhǎng)度固定而又關(guān)于對(duì)稱軸對(duì)稱、點(diǎn)),(),(軸交于點(diǎn)與拋物線、解:21Q211331303:30C3320BCCQBQCQACACACQCQACQBQABA)2(32)3)(1(03B01A)1(411111112Q A CQ A C22?????????