九年级数学上22一元二次方程的解法教案新版湘教版.docx
- 文档编号:17896562
- 上传时间:2023-08-04
- 格式:DOCX
- 页数:9
- 大小:24.24KB
九年级数学上22一元二次方程的解法教案新版湘教版.docx
《九年级数学上22一元二次方程的解法教案新版湘教版.docx》由会员分享,可在线阅读,更多相关《九年级数学上22一元二次方程的解法教案新版湘教版.docx(9页珍藏版)》请在冰点文库上搜索。
九年级数学上22一元二次方程的解法教案新版湘教版
2018年九年级数学上2.2一元二次方程的解法教案新版湘教版
2锛?
銆€涓€鍏冧簩娆℃柟绋嬬殑瑙f硶2锛?
.1銆€閰嶆柟娉?
鏁欏鐩爣銆愮煡璇嗕笌鎶€鑳姐€?
1锛庣煡閬撹В涓€鍏冧簩娆℃柟绋嬬殑鍩烘湰鎬濊矾鏄€滈檷娆♀€濆寲涓€鍏冧簩娆℃柟绋嬩负涓€鍏冧竴娆℃柟绋嬶紟2锛庡浼氱敤鐩存帴寮€骞虫柟娉曡В褰㈠(ax锛媌)2锛峩锛?
(k鈮?
)鐨勬柟绋嬶紟3锛庣悊瑙b€滈厤鏂光€濇槸涓€绉嶅父鐢ㄧ殑鏁板鏂规硶锛屽湪鐢ㄩ厤鏂规硶灏嗕竴鍏冧簩娆℃柟绋嬪彉褰㈢殑杩囩▼涓紝璁╁鐢熻繘涓€姝ヤ綋浼氬寲褰掔殑鎬濇兂鏂规硶锛?
銆愯繃绋嬩笌鏂?
娉曘€?
閫氳繃鎺㈢储閰嶆柟娉曠殑杩囩▼锛岃瀛︾敓浣撲細杞寲鐨勬暟瀛︽€濇兂鏂规硶锛?
銆愭儏鎰熸€佸害銆?
瀛︾敓鍦ㄧ嫭绔嬫€濊€冨拰鍚堜綔鎺㈢┒涓劅鍙楁垚鍔熺殑鍠滄偊锛屽苟浣撻獙鏁板鐨勪环鍊硷紝澧炲己瀛︾敓瀛︿範鏁板鐨勫叴瓒o紟銆愭暀瀛﹂噸鐐广€?
杩愮敤閰嶆柟娉曡В涓€鍏冧簩娆℃柟绋嬶紟銆愭暀瀛﹂毦鐐广€?
鎶婁竴鍏冧簩娆℃柟绋嬭浆鍖栦负褰㈠(x锛媙)2锛漝(d鈮?
)鐨勮繃绋嬶紟鏁欏杩囩▼涓€銆佹儏鏅鍏ワ紝鍒濇璁ょ煡1锛庢牴鎹畬鍏ㄥ钩鏂瑰叕寮忓~绌猴細
(1)x2锛?
x锛?
锛?
銆€銆€)2
(2)x2锛?
x锛?
6锛?
銆€銆€)2(3)x2锛?
0x锛?
銆€銆€)2锛?
銆€銆€)2(4)x2锛?
x锛?
銆€銆€)2锛?
銆€銆€)22锛庡墠闈㈡垜浠凡缁忓浜嗕竴鍏冧竴娆℃柟绋嬪拰浜屽厓涓€娆℃柟绋嬬粍鐨勮В娉曪紝瑙d簩鍏冧竴娆℃柟绋嬬粍鐨勫熀鏈€濊矾鏄粈涔堬紵(娑堝厓銆佸寲浜屽厓涓€娆℃柟绋嬬粍涓轰竴鍏冧竴娆℃柟绋?
锛庣敱瑙d簩鍏冧竴娆℃柟绋嬬粍鐨勫熀鏈€濊矾锛屼綘鑳芥兂鍑鸿В涓€鍏冧簩娆℃柟绋嬬殑鍩烘湰鎬濊矾鍚楋紵3锛庝綘浼氳В鏂圭▼x2锛?
x锛?
6锛?
鍚楋紵浣犱細灏嗗畠鍙樻垚(x锛媘)2锛漬(n涓洪潪璐熸暟)鐨勫舰寮忓悧锛熻瘯璇曠湅锛庡鏋滄槸鏂圭▼2x2锛?
锛?
x鍛紵銆愭暀瀛﹁鏄庛€戝浼氬埄鐢ㄥ畬鍏ㄥ钩鏂圭煡璇嗗~绌猴紝鍒濇閰嶆柟涓哄悗闈㈠涔犳墦涓嬪熀纭€锛?
浜屻€佹€濊€冩帰绌讹紝鑾峰彇鏂扮煡1锛庤В鏂圭▼锛歺2锛?
500锛?
.闂細鎬庢牱灏嗚繖涓柟绋嬧€滈檷娆♀€濅负涓€鍏冧竴娆℃柟绋嬶紵鎶婃柟绋嬪啓鎴恱2锛?
500杩欒〃鏄巟鏄?
500鐨勫钩鏂规牴锛屾牴鎹钩鏂规牴鐨勬剰涔夛紝寰?
x锛?
500鎴杧锛濓紞2500鍥犳锛屽師鏂圭▼鐨勮В涓簒1锛?
0锛寈2锛濓紞50銆愬綊绾崇粨璁恒€戜竴鍏冧簩娆℃柟绋嬬殑瑙d篃鏄竴鍏冧簩娆℃柟绋嬬殑鏍癸紟2锛庤В鏂圭▼(2x锛?
)2锛?
瑙o細鏍规嵁骞虫柟鏍圭殑鎰忎箟锛屽緱2x锛?
锛?
鎴?
x锛?
锛濓紞2鍥犳锛屽師鏂圭▼鐨勬牴涓?
x1锛?
锛?
2锛寈2锛濓紞2锛?
23锛庨€氳繃涓婇潰鐨勪袱涓緥棰橈紝浣犵煡閬撲粈涔堟椂鍊欑敤寮€骞虫柟鐨勬柟娉曟潵瑙d竴鍏冧簩娆℃柟绋嬪憿锛?
銆愬綊绾崇粨璁恒€戝浜庡舰濡?
x锛媙)2锛漝(d鈮?
)鐨勬柟绋嬶紝鍙洿鎺ョ敤寮€骞虫柟娉曡В锛?
鐩存帴寮€骞虫柟娉曠殑姝ラ鏄細鎶婃柟绋嬪彉褰㈡垚(x锛媙)2锛漝(d鈮?
)锛岀劧鍚庣洿鎺ュ紑骞虫柟寰梮锛媙锛濆拰x锛媙锛濓紞锛屽垎鍒В杩欎袱涓竴鍏冧竴娆℃柟绋嬶紝寰楀埌鐨勮В灏辨槸鍘熶竴鍏冧簩娆℃柟绋嬬殑瑙o紟4锛庤В鏂圭▼x2锛?
x锛?
2鎴戜滑宸茬煡锛屽鏋滄妸鏂圭▼x2锛?
x锛?
2鍐欐垚(x锛媙)2锛漝鐨勫舰寮忥紝閭d箞灏卞彲浠ユ牴鎹钩鏂规牴鐨勬剰涔夋潵姹傝В锛?
閭d箞锛屽浣曞皢宸﹁竟鍐欐垚(x锛媙)2鐨勫舰寮忓憿锛?
鎴戜滑瀛﹁繃瀹屽叏骞虫柟寮忥紝浣犺兘鍚﹀皢宸﹁竟x2锛?
x娣讳笂涓€椤逛娇瀹冩垚涓轰竴涓畬鍏ㄥ钩鏂瑰紡锛庤鐩镐簰浜ゆ祦锛?
鍐欏嚭瑙i杩囩▼锛?
銆愬綊绾崇粨璁恒€戜竴鑸湴锛屽儚涓婇潰杩欐牱锛屽湪鏂圭▼x2锛?
x锛?
2鐨勫乏杈瑰姞涓婁竴娆¢」绯绘暟鐨勪竴鍗婄殑骞虫柟锛屽湪鍑忓幓杩欎釜鏁帮紝浣垮緱鍚湭鐭ユ暟鐨勯」鍦ㄤ竴涓畬鍏ㄥ钩鏂瑰紡閲岋紝杩欑鍋氭硶鍙綔閰嶆柟锛庨厤鏂广€佹暣鐞嗗悗灏卞彲浠ョ洿鎺ユ牴鎹钩鏂规牴鐨勬剰涔夋潵姹傝В浜嗭紟杩欑瑙d竴鍏冧簩娆℃柟绋嬬殑鏂规硶鍙綔閰嶆柟娉曪紟5锛庡浣曠敤閰嶆柟娉曡В鏂圭▼25x2锛?
0x锛?
1锛?
鍛紵濡傛灉浜屾椤圭郴鏁颁负1锛岄偅灏卞ソ鍔炰簡锛侀偅涔堟€庢牱灏嗕簩娆¢」鐨勭郴鏁板寲涓?
鍛紵鍚屼即涔嬮棿鍙互鐩镐簰浜ゆ祦锛?
璇曠潃鍐欏嚭瑙i杩囩▼锛?
6锛庨€氳繃涓婇潰閰嶆柟娉曡В涓€鍏冧簩娆℃柟绋嬬殑杩囩▼锛屼綘鑳芥€荤粨鐢ㄩ厤鏂规硶瑙d竴鍏冧簩娆℃柟绋嬬殑姝ラ鍚楋紵銆愬綊绾崇粨璁恒€戠敤閰嶆柟娉曡В涓€鍏冧簩娆℃柟绋嬬殑姝ラ锛?
(1)鎶婃柟绋嬪寲涓轰竴鑸舰寮廰x2锛媌x锛媍锛?
锛?
(2)鎶婃柟绋嬬殑甯告暟椤归€氳繃绉婚」绉诲埌鏂圭▼鐨勫彸杈癸紱(3)鑻ユ柟绋嬬殑浜屾椤圭郴鏁颁笉涓?
鏃讹紝鏂圭▼涓よ竟鍚屾椂闄や互浜屾椤圭郴鏁癮锛?
(4)鏂圭▼涓よ竟鍚屾椂鍔犱笂涓€娆¢」绯绘暟涓€鍗婄殑骞虫柟锛?
(5)姝ゆ椂鏂圭▼鐨勫乏杈规槸涓€涓畬鍏ㄥ钩鏂瑰紡锛岀劧鍚庡埄鐢ㄥ钩鏂规牴鐨勫畾涔夋妸涓€鍏冧簩娆℃柟绋嬪寲涓轰袱涓竴鍏冧竴娆℃柟绋嬫潵瑙o紟銆愭暀瀛﹁鏄庛€戦€氳繃杩欎竴杩囩▼锛屽鐢熷彂鐜拌兘鐢ㄧ洿鎺ュ紑骞虫柟娉曟眰瑙g殑鏂圭▼閮藉彲浠ヨ浆鍖栨垚涓€鑸舰寮忥紝涓€鑸舰寮忕殑鏂圭▼涔熻兘鐢ㄩ厤鏂规硶杞寲涓哄彲浠ョ洿鎺ュ紑骞虫柟鐨勫舰寮忥紝鎵€浠ユ€荤粨鍑鸿В涓€鍏冧簩娆℃柟绋嬬殑鍩烘湰鎬濊矾鏄皢涓€鍏冧簩娆℃柟绋嬭浆鍖栦负(x锛媙)2锛漝(d鈮?
)鐨勫舰寮忥紟涓夈€佽繍鐢ㄦ柊鐭ワ紝娣卞寲鐞?
瑙?
1锛庤鏁欐潗P33渚?
銆丳34渚?
.2锛庡垪鏂圭▼(娉細瀛︾敓缁冧範锛屾暀甯堝贰瑙嗭紝閫傚綋杈呭锛?
(1)x2锛?
0x锛?
4锛?
锛?
(2)(2x锛?
)(x锛?
)锛?
锛?
(3)3x2锛?
x锛?
锛?
.瑙o細
(1)绉婚」锛屽緱x2锛?
0x锛濓紞24閰嶆柟锛屽緱x2锛?
0x锛?
5锛濓紞24锛?
5锛?
鐢辨鍙緱(x锛?
)2锛?
锛?
x锛?
锛澛?
锛?
鈭磝1锛?
锛寈2锛?
.
(2)鏁寸悊锛屽緱2x2锛?
x锛?
锛?
.绉婚」锛屽緱2x2锛?
x锛?
浜屾椤圭郴鏁板寲涓?
寰梮2锛?
2x锛?
锛?
閰嶆柟锛屽緱x2锛?
2x锛?
54)2锛?
锛?
54)2(x锛?
4)2锛?
916锛?
鐢辨鍙緱x锛?
4锛澛?
94锛?
x1锛濓紞5锛?
94锛寈2锛濓紞5锛?
94.(3)绉婚」锛屽緱3x2锛?
x锛濓紞4浜屾椤圭郴鏁板寲涓?
锛屽緱x2锛?
x锛濓紞43锛?
閰嶆柟锛屽緱x2锛?
x锛?
2锛濓紞43锛?
2锛?
(x锛?
)2锛濓紞13鍥犱负瀹炴暟鐨勫钩鏂逛笉浼氭槸璐熸暟锛屾墍浠鍙栦换浣曞疄鏁版椂锛?
x锛?
)2閮芥槸闈炶礋鏁帮紝涓婂紡閮戒笉鎴愮珛锛屽嵆鍘熸柟绋嬫棤瀹炴暟鏍癸紟3锛庤В鏂圭▼x2锛?
x锛?
锛?
鍒嗘瀽锛氭樉鐒惰繖涓柟绋嬬殑宸﹁竟涓嶆槸涓€涓畬鍏ㄥ钩鏂瑰紡锛屽洜姝わ紝瑕佹寜鍓嶉潰鐨勬柟娉曞寲涓哄畬鍏ㄥ钩鏂瑰紡锛?
瑙o細x2锛?
x锛?
锛?
绉婚」寰楋細x2锛?
x锛濓紞1閰嶆柟寰楋細x2锛?
x锛?
6锛濓紞1锛?
6鍗?
x锛?
)2锛?
5涓よ竟寮€骞虫柟寰楋細x锛?
锛澛?
5鈭磝1锛?
锛?
5锛寈2锛?
锛?
5.4锛庣敤閰嶆柟娉曞皢涓嬪垪鍚勫紡鍖栦负a(x锛媓)2锛媖鐨勫舰寮忥紟
(1)锛?
x2锛?
x锛?
锛?
2)23y2锛?
3y锛?
锛?
(3)0.4x2锛?
.8x锛?
.瑙o細
(1)锛?
x2锛?
x锛?
锛濓紞3(x2锛?
x锛?
3)锛濓紞3(x2锛?
x锛?
2锛?
2锛?
3)锛濓紞3[(x锛?
)2锛?
3]锛濓紞3(x锛?
)2锛?
(2)23y2锛?
3y锛?
锛?
3(y2锛?
2y锛?
)锛?
3[y2锛?
2y锛?
14)2锛?
14)2锛?
]锛?
3[(y锛?
4)2锛?
916]锛?
3(y锛?
4)2锛?
924.(3)0.4x2锛?
.8x锛?
锛?
.4(x2锛?
x锛?
.5)锛?
.4[(x2锛?
x锛?
2)锛?
2锛?
.5]锛?
.4(x锛?
)2锛?
.4銆愭暀瀛﹁鏄庛€戦€氳繃缁冧範锛屼娇瀛︾敓鑳界伒娲昏繍鐢ㄢ€滈厤鏂规硶鈥濓紝骞跺己鍖栧鐢熷涓€鍏冧簩娆℃柟绋嬭В鐨勮璇嗭紟鍥涖€佸笀鐢熶簰鍔ㄣ€佽鍫傚皬缁?
鍏堝皬缁勫唴浜ゆ祦鏀惰幏鍜屾劅鎯筹紝鑰屽悗浠ュ皬缁勪负鍗曚綅娲句唬琛ㄨ繘琛屾€荤粨锛庢暀甯堜綔浠ヨˉ鍏咃紟璇惧悗浣滀笟甯冪疆浣滀笟锛氭暀鏉愨€滀範棰?
.2鈥濅腑绗?
銆?
銆?
棰橈紟鏁欏鍙嶆€?
鍦ㄦ暀瀛﹁繃绋嬩腑锛屽潥鎸佺敱绠€鍗曞埌澶嶆潅锛岀敱鐗规畩鍒颁竴鑸殑鍘熷垯锛岄噰鐢ㄤ簡瑙傚療瀵规瘮锛屽悎浣滄帰绌剁瓑涓嶅悓鐨勫涔犳柟寮忥紝鍏呭垎鍙戞尌瀛︾敓鐨勪富浣撲綔鐢紝璁╁鐢熶富鍔ㄦ帰绌跺彂鐜扮粨璁猴紝鏁欏笀鍋氬鐢熷涔犵殑寮曞鑰咃紝鍚堜綔鑰咃紝淇冭繘鑰咃紝瑕侀€傛椂榧撳姳瀛︾敓锛屽疄鐜板笀鐢熶簰鍔紟鍚屾椂锛屾垜璁よ瘑鍒版暀甯堜笉浠呬粎瑕佹暀缁欏鐢熺煡璇嗭紝鏇磋鍦ㄦ暀瀛︿腑娓楅€忔暟瀛︿腑鐨勬€濇兂鏂规硶锛屽煿鍏诲鐢熻壇濂界殑鏁板绱犲吇鍜屽涔犺兘鍔涳紝璁╁鐢熷浼氬涔狅紟
2锛?
.2銆€鍏紡娉?
鏁欏鐩爣銆愮煡璇嗕笌鎶€鑳姐€?
1锛庣粡鍘嗘帹瀵兼眰鏍瑰叕寮忕殑杩囩▼锛屽姞寮烘帹鐞嗘妧鑳界殑璁粌锛?
2锛庝細鐢ㄥ叕寮忔硶瑙g畝鍗曠郴鏁扮殑涓€鍏冧簩娆℃柟绋嬶紟銆愯繃绋嬩笌鏂规硶銆?
閫氳繃鐢遍厤鏂规硶鎺ㄥ姹傛牴鍏紡锛屽煿鍏诲鐢熸帹鐞嗚兘鍔涘拰鐢辩壒娈婂埌涓€鑸殑鏁板鎬濇兂锛?
銆愭儏鎰熸€佸害銆?
璁╁鐢熶綋楠屽埌鎵€鏈変竴鍏冧簩娆℃柟绋嬮兘鑳借繍鐢ㄥ叕寮忔硶鍘昏В锛屽舰鎴愬叏闈㈣В鍐抽棶棰樼殑绉瀬鎯呮劅锛屾劅鍙楀叕寮忕殑瀵圭О缇庛€佺畝娲佺編锛屼骇鐢熺儹鐖辨暟瀛︾殑鎯呮劅锛?
銆愭暀瀛﹂噸鐐广€?
姹傛牴鍏紡鐨勬帹瀵煎拰鍏紡娉曠殑搴旂敤锛?
銆愭暀瀛﹂毦鐐广€?
鐞嗚В姹傛牴鍏紡鐨勬帹瀵艰繃绋嬶紟鏁欏杩囩▼涓€銆佹儏鏅鍏ワ紝鍒濇璁ょ煡1锛庣敤閰嶆柟娉曡В鏂圭▼锛?
(1)x2锛?
x锛?
锛?
锛?
2)2x2锛?
x锛?
锛?
.2锛庣敱鐢ㄩ厤鏂规硶瑙d竴鍏冧簩娆℃柟绋嬬殑鍩烘湰姝ラ鐭ワ細瀵逛簬姣忎釜鍏蜂綋鐨勪竴鍏冧簩娆℃柟绋嬶紝閮戒娇鐢ㄤ簡鐩稿悓鐨勪竴浜涜绠楁楠わ紝杩欏惎鍙戞垜浠€濊€冿紝鑳戒笉鑳藉涓€鑸舰寮忕殑涓€鍏冧簩娆℃柟绋媋x2锛媌x锛媍锛?
(a鈮?
)浣跨敤杩欎簺姝ラ锛岀劧鍚庢眰鍑鸿Вx鐨勫叕寮忥紵銆愭暀瀛﹁鏄庛€戣繖鏍峰仛浜嗕互鍚庯紝鎴戜滑鍙互杩愮敤杩欎釜鍏紡鏉ユ眰姣忎竴涓叿浣撶殑涓€鍏冧簩娆℃柟绋嬬殑瑙o紝鍙栧緱涓€閫氱櫨閫氱殑鏁堟灉锛?
浜屻€佹€濊€冩帰绌讹紝鑾峰彇鏂扮煡1锛庣敤閰嶆柟娉曡В鏂圭▼锛歛x2锛媌x锛媍锛?
(a鈮?
)鍒嗘瀽锛氬墠闈㈠叿浣撴暟瀛楀凡鍋氫簡寰堝锛屾垜浠幇鍦ㄤ笉濡ㄦ妸a銆乥銆乧涔熷綋鎴愪竴涓叿浣撴暟瀛楋紝鏍规嵁涓婇潰鐨勮В棰樻楠ゅ氨鍙互涓€鐩存帹涓嬪幓锛?
瑙o細绉婚」锛屽緱锛歛x2锛媌x锛濓紞c鍥犱负a鈮?
锛屾墍浠ユ柟绋嬩袱杈瑰悓闄や互a寰楋細x2锛媌ax锛濓紞ca閰嶆柟锛屽緱锛歺2锛媌ax锛?
b2a)2锛濓紞ca锛?
b2a)2鍗?
x锛媌2a)2锛漛2锛?
ac4a2鈭礱鈮?
锛屸埓4a2>0褰揵2锛?
ac鈮?
锛宐2锛?
ac4a2鈮?
鈭磝锛媌2a锛澛眀2锛?
ac2a鍗硏锛濓紞b卤b2锛?
ac2a鈭磝1锛濓紞b锛媌2锛?
ac2a锛?
x2锛濓紞b锛峛2锛?
ac2a.褰揵2锛?
ac<0鏃讹紝鏂圭▼鏃犺В锛?
銆愬綊绾崇粨璁恒€戠敱涓婂彲鐭ワ紝涓€鍏冧簩娆℃柟绋媋x2锛媌x锛媍锛?
(a鈮?
)鐨勬牴鐢辨柟绋嬬殑绯绘暟a銆乥銆乧鑰屽畾锛屽洜姝わ細
(1)瑙d竴鍏冧簩娆℃柟绋嬫椂锛屽彲浠ュ厛灏嗘柟绋嬪寲涓轰竴鑸舰寮廰x2锛媌x锛媍锛?
锛屽綋b2锛?
ac鈮?
鏃讹紝灏哸銆乥銆乧浠e叆寮忓瓙x锛濓紞b卤b2锛?
ac2a(b2锛?
ac鈮?
)灏卞彲姹傚嚭鏂圭▼鐨勬牴锛?
(2)杩欎釜寮忓瓙鍙仛涓€鍏冧簩娆℃柟绋嬬殑姹傛牴鍏紡锛?
(3)鍒╃敤姹傛牴鍏紡瑙d竴鍏冧簩娆℃柟绋嬬殑鏂规硶鍙叕寮忔硶锛?
銆愬己璋冦€戠敤鍏紡娉曡В涓€鍏冧簩娆℃柟绋嬫椂锛屽繀椤绘敞鎰忎袱鐐癸細
(1)灏哸銆乥銆乧鐨勫€间唬鍏ュ叕寮忔椂锛屼竴瀹氳娉ㄦ剰绗﹀彿涓嶈兘鍑洪敊锛?
2)寮忓瓙b2锛?
ac鈮?
鏄叕寮忕殑涓€閮ㄥ垎锛?
銆愭暀瀛﹁鏄庛€戣瀛︾敓鎬濊€冨浜庝竴鑸舰寮忕殑涓€鍏冧簩娆℃柟绋媋x2锛媌x锛媍锛?
(a鈮?
)鑳藉惁鐢ㄩ厤鏂规硶姹傚嚭瀹冪殑瑙o紵閫氳繃瑙f柟绋嬪彂鐜板綊绾充竴鍏冧簩娆℃柟绋嬬殑姹傛牴鍏紡锛?
2锛庡睍绀鸿鏈琍36渚?
(1)锛?
2)锛屾寜璇炬湰鏂瑰紡寮曞瀛︾敓鐢ㄥ叕寮忔硶瑙d竴鍏冧簩娆℃柟绋嬶紝骞舵彁閱掑鐢熷湪纭畾a锛宐锛宑鐨勫€兼椂锛屽厛瑕佸皢涓€鍏冧簩娆℃柟绋嬪紡鍖栦负涓€鑸舰寮忥紝娉ㄦ剰a锛宐锛宑鐨勭鍙凤紟3锛庡紩瀵煎鐢熷畬鎴怭37渚?
.4锛庝綘鑳芥€荤粨鍑虹敤鍏紡娉曡В涓€鍏冧簩娆℃柟绋嬬殑涓€鑸楠ゅ悧锛?
銆愬綊绾崇粨璁恒€戦鍏堣鎶婂師鏂圭▼鍖栦负涓€鑸舰寮忥紝浠庤€屾纭湴纭畾a锛宐锛宑鐨勫€硷紱鍏舵瑕佽绠梑2锛?
ac鐨勫€硷紝褰揵2锛?
ac鈮?
鏃讹紝鍐嶇敤姹傛牴鍏紡姹傝В锛?
涓夈€佽繍鐢ㄦ柊鐭ワ紝娣卞寲鐞嗚В1锛庣敤鍏紡娉曡В涓嬪垪鏂圭▼锛?
2x2锛?
锛?
x鍒嗘瀽锛氱敤鍏紡娉曡В涓€鍏冧簩娆℃柟绋嬶紝闇€鍏堢‘瀹歛銆乥銆乧鐨勫€笺€佸啀绠楀嚭b2锛?
ac鐨勫€笺€佹渶鍚庝唬鍏ユ眰鏍瑰叕寮忔眰瑙o紟銆€銆€瑙o細2x2锛?
x锛?
锛?
a锛?
锛宐锛濓紞7锛宑锛?
鈭礲2锛?
ac锛?
锛?
)2锛?
脳2脳3锛?
5>0鈭磝锛濓紞b卤b2锛?
ac2a锛?
卤252脳2锛?
卤54鍗硏1锛?
锛寈2锛?
2.2锛庢煇鏁板鍏磋叮灏忕粍瀵瑰叧浜巟鐨勬柟绋?
m锛?
)xm2锛?
锛?
m锛?
)x锛?
锛?
鎻愬嚭浜嗕笅鍒楅棶棰橈紟
(1)鑻ヤ娇鏂圭▼涓轰竴鍏冧簩娆℃柟绋嬶紝m鏄惁瀛樺湪锛熻嫢瀛樺湪锛屾眰鍑簃骞惰В姝ゆ柟绋嬶紟
(2)鑻ヤ娇鏂圭▼涓轰竴鍏冧竴娆℃柟绋媘鏄惁瀛樺湪锛熻嫢瀛樺湪锛岃姹傚嚭锛?
浣犺兘瑙e喅杩欎釜闂鍚楋紵鍒嗘瀽锛?
1)瑕佷娇瀹冧负涓€鍏冧簩娆℃柟绋嬶紝蹇呴』婊¤冻m2锛?
锛?
锛屽悓鏃惰繕瑕佹弧瓒?
m锛?
)鈮?
.
(2)瑕佷娇瀹冧负涓€鍏冧竴娆℃柟绋嬶紝蹇呴』婊¤冻鈭?
鈶爉2锛?
锛?
锛坢锛?
锛夛紜锛坢锛?
锛夆墵0鎴栤憽m2锛?
锛?
m锛?
鈮?
鎴?
鈶锛?
锛?
m锛?
鈮?
瑙o細
(1)瀛樺湪锛庢牴鎹鎰忥紝寰楋細m2锛?
锛?
m2锛?
銆€m锛澛?
褰搈锛?
鏃讹紝m锛?
锛?
锛?
锛?
鈮?
褰搈锛濓紞1鏃讹紝m锛?
锛濓紞1锛?
锛?
(涓嶅悎棰樻剰锛岃垗鍘?
鈭村綋m锛?
鏃讹紝鏂圭▼涓?
x2锛?
锛峹锛?
a锛?
锛宐锛濓紞1锛宑锛濓紞1b2锛?
ac锛?
锛?
)2锛?
脳2脳(锛?
)锛?
锛?
锛?
x锛濓紞锛堬紞1锛壜?
2脳2锛?
卤34x1锛?
锛寈2锛濓紞12.鍥犳锛岃鏂圭▼鏄竴鍏冧簩娆℃柟绋嬫椂锛宮锛?
锛屼袱鏍箈1锛?
锛寈2锛濓紞12.
(2)瀛樺湪锛庢牴鎹鎰忥紝寰楋細鈶爉2锛?
锛?
锛宮2锛?
锛宮锛?
鍥犱负褰搈锛?
鏃讹紝(m锛?
)锛?
m锛?
)锛?
m锛?
锛濓紞1鈮?
鎵€浠锛?
婊¤冻棰樻剰锛?
鈶″綋m2锛?
锛?
锛宮涓嶅瓨鍦紟鈶㈠綋m锛?
锛?
锛屽嵆m锛濓紞1鏃讹紝m锛?
锛濓紞3鈮?
鎵€浠锛濓紞1涔熸弧瓒抽鎰忥紟褰搈锛?
鏃讹紝涓€鍏冧竴娆℃柟绋嬫槸x锛?
x锛?
锛?
锛?
瑙e緱锛歺锛濓紞1褰搈锛濓紞1鏃讹紝涓€鍏冧竴娆℃柟绋嬫槸锛?
x锛?
锛?
瑙e緱x锛濓紞13鍥犳锛屽綋m锛?
鎴栵紞1鏃讹紝璇ユ柟绋嬫槸涓€鍏冧竴娆℃柟绋嬶紝骞朵笖褰搈锛?
鏃讹紝鍏舵牴涓簒锛濓紞1锛涘綋m锛濓紞1鏃讹紝鍏朵竴鍏冧竴娆℃柟绋嬬殑鏍逛负x锛濓紞13.
銆愭暀瀛﹁鏄庛€戜富浣撴帰绌躲€佹帰绌跺埄鐢ㄥ叕寮忔硶瑙d竴鍏冧簩娆℃柟绋嬬殑涓€鑸柟娉曪紝杩涗竴姝ョ悊瑙f眰鏍瑰叕寮忥紟鍥涖€佸笀鐢熶簰鍔ㄣ€佽鍫傚皬缁?
鍏堝皬缁勫唴浜ゆ祦鏀惰幏鍜屾劅鎯宠€屽悗浠ュ皬缁勪负鍗曚綅娲句唬琛ㄨ繘琛屾€荤粨锛庢暀甯堜綔浠ヨˉ鍏咃紟璇惧悗浣滀笟甯冪疆浣滀笟锛氭暀鏉愨€滀範棰?
.2鈥濅腑绗?
棰橈紟鏁欏鍙嶆€?
閫氳繃澶嶄範閰嶆柟娉曚娇瀛︾敓浼氬涓€鍏冧簩娆℃柟绋嬬殑瀹氫箟鍙婅В娉曟湁涓€涓啛鎮夌殑鍗拌薄锛庣劧鍚庤瀛︾敓鐢ㄩ厤鏂规硶鎺ㄥ涓€鑸舰寮廰x2锛媌x锛媍锛?
(a鈮?
)鐨勮В锛屽苟鎺屾彙鍒╃敤鏍圭殑鍒ゅ埆寮忓垽鏂竴鍏冧簩娆℃柟绋嬫牴鐨勬儏鍐碉紟浣垮鐢熺殑鎺ㄧ悊鑳藉姏寰楀埌鍔犲己锛?
2锛?
.3銆€鍥犲紡鍒嗚В娉?
鏁欏鐩爣銆愮煡璇嗕笌鎶€鑳姐€?
鑳界伒娲昏繍鐢ㄧ洿鎺ュ紑骞虫柟娉曘€侀厤鏂规硶銆佸叕寮忔硶鍙婂洜寮忓垎瑙f硶瑙d竴鍏冧簩娆℃柟绋嬶紟鑳藉鏍规嵁涓€鍏冧簩娆℃柟绋嬬殑缁撴瀯鐗圭偣锛岀伒娲绘嫨鍏剁畝鍗曠殑鏂规硶锛?
銆愯繃绋嬩笌鏂规硶銆?
閫氳繃姣旇緝銆佸垎鏋愩€佺患鍚堬紝鍩瑰吇瀛︾敓鍒嗘瀽闂瑙e喅闂鐨勮兘鍔涳紟銆愭儏鎰熸€佸害銆?
閫氳繃鐭ヨ瘑涔嬮棿鐨勭浉浜掕仈绯伙紝鍩瑰吇瀛︾敓鐢ㄨ仈绯诲拰鍙戝睍鐨勭溂鍏夊垎鏋愰棶棰橈紝瑙e喅闂锛屾爲绔嬭浆鍖栫殑鎬濇兂鏂规硶锛?
銆愭暀瀛﹂噸鐐广€?
鐢ㄥ洜寮忓垎瑙f硶瑙d竴鍏冧簩娆℃柟绋嬶紟銆愭暀瀛﹂毦鐐广€?
鐞嗚В鍥犲紡鍒嗚В娉曡В涓€鍏冧簩娆℃柟绋嬬殑鍩烘湰鎬濇兂锛?
鏁欏杩囩▼涓€銆佹儏鏅鍏ワ紝鍒濇璁ょ煡澶嶄範锛氬皢涓嬪垪鍚勫紡鍒嗚В鍥犲紡
(1)5x2锛?
x
(2)x2锛?
x锛?
(3)4x(x锛?
)锛?
锛?
x(4)x2锛?
(5)(2x锛?
)2锛峹2銆愭暀瀛﹁鏄庛€戦€氳繃澶嶄範鐩稿叧鐭ヨ瘑锛屾湁鍒╀簬瀛︾敓鐔熺粌姝g‘灏嗗椤瑰紡鍥犲紡鍒嗚В锛屼粠鑰屾湁鍒╅檷浣庢湰鑺傜殑闅惧害锛?
浜屻€佹€濊€冩帰绌讹紝鑾峰彇鏂扮煡1锛庤В鏂圭▼銆€銆€x2锛?
x锛?
鍙敤鍥犲紡鍒嗚В娉曟眰瑙?
鏂圭▼宸﹁竟鎻愬彇鍏洜寮弜锛屽緱x(x锛?
)锛?
鐢辨寰梮锛?
鎴杧锛?
锛?
鍗硏1锛?
锛寈2锛?
涓庡叕寮忔硶鐩告瘮锛屽摢绉嶆洿绠€鍗曪紵銆愬綊绾崇粨璁恒€戝埄鐢ㄥ洜寮忓垎瑙f潵瑙d竴鍏冧簩娆℃柟绋嬬殑鏂规硶鍙仛鍥犲紡鍒嗚В娉曪紟2锛庣敤鍥犲紡鍒嗚В娉曡В涓嬪垪鏂圭▼锛?
(1)x(x锛?
)锛?
x锛?
(2)2x(5x锛?
)锛?
(5x锛?
)锛?
(3)(35锛?
x)2锛?
00锛?
.3锛庝綘鑳芥€荤粨鍥犲紡鍒嗚В娉曡В涓€鍏冧簩娆℃柟绋嬬殑涓€鑸楠ゅ悧锛?
銆愬綊绾崇粨璁恒€戞妸鏂圭▼鍖栨垚涓€杈逛负0锛屽彟涓€杈规槸涓や釜涓€娆″洜寮忕殑涔樼Н鐨勫舰寮忥紝鐒跺悗浣挎瘡涓€涓竴娆″洜寮忕瓑浜?
锛屽垎鍒В涓や釜涓€鍏冧竴娆℃柟绋嬶紝寰楀埌鐨勪袱涓В灏辨槸鍘熶竴鍏冧簩娆℃柟绋嬬殑瑙o紟4锛庤涓€璇?
锛氬洜寮忓垎瑙f硶閫傜敤浜庤В浠€涔堝舰寮忕殑涓€鍏冧簩娆℃柟绋嬶紟銆愬綊绾崇粨璁恒€戝洜寮忓垎瑙f硶閫傜敤浜庤В涓€杈逛负0锛屽彟涓€杈瑰彲鍒嗚В鎴愪袱涓竴娆″洜寮忎箻绉殑涓€鍏冧簩娆℃柟绋嬶紟5锛庨€夋嫨鍚堥€傜殑鏂规硶瑙d笅鍒楁柟绋嬶細
(1)x2锛?
x锛?
锛?
(2)5x2锛?
x锛?
锛?
锛?
(3)x2锛?
x锛?
锛?
.鎸夎鏈柟寮忓紩瀵煎鐢熺敤鍥犲紡鍒嗚В娉曡В涓€鍏冧簩娆℃柟绋嬶紟6锛庡浣曢€夋嫨鍚堥€傜殑鏂规硶瑙d竴鍏冧簩娆℃柟绋嬪憿锛?
銆愬綊绾崇粨璁恒€戝叕寮忔硶閫傜敤浜庢墍鏈変竴鍏冧簩娆℃柟绋嬶紟鍥犲紡鍒嗚В娉?
鏈夋椂闇€瑕佸厛閰嶆柟)閫傜敤浜庢墍鏈変竴鍏冧簩娆℃柟绋嬶紟閰嶆柟娉曟槸涓轰簡鎺ㄥ鍑烘眰鏍瑰叕寮忥紝浠ュ強鍏堥厤鏂癸紝鐒跺悗鐢ㄥ洜寮忓垎瑙f硶锛?
鎬讳箣锛岃В涓€鍏冧簩娆℃柟绋嬬殑鍩烘湰鎬濊矾閮芥槸锛氬皢涓€鍏冧簩娆℃柟绋嬭浆鍖栨垚涓轰竴鍏冧竴娆℃柟绋嬶紝鍗抽檷娆★紝鍏舵湰璐ㄦ槸鎶婃柟绋媋x2锛媌x锛媍锛?
(a鈮?
)鐨勫乏杈圭殑浜屾澶氶」寮忓垎瑙f垚涓や釜涓€娆″椤瑰紡鐨勪箻绉紝鍗砤x2锛媌x锛媍锛漚(x锛峹1)(x锛峹2)锛屽叾涓瓁1鍜寈2鏄柟绋媋x2锛媌x锛媍锛?
鐨勪袱涓牴锛?
銆愭暀瀛﹁鏄庛€戝湪瀛︾敓瑙e喅闂鐨勫熀纭€涓婂紩瀵煎鐢熸帰绱㈠埄鐢ㄥ洜寮忓垎瑙hВ鏂圭▼鐨勬柟娉曪紝鎰熷彈鍥犲紡鍒嗚В鐨勪綔鐢ㄤ互鍙婅兘澶熻В鏂圭▼鐨勪緷鎹紟涓夈€佽繍鐢ㄦ柊鐭ワ紝娣卞寲鐞嗚В1锛庣敤鍥犲紡鍒嗚В娉曡В涓嬪垪鏂圭▼锛?
(1)5x2锛?
x锛?
锛?
(2)7x(3锛峹)锛?
(x锛?
)锛?
鍒嗘瀽锛?
1)宸﹁竟锛漻(5x锛?
)锛屽彸杈癸紳0锛?
2)鍏堟妸鍙宠竟鍖栦负0锛?
x(3锛峹)锛?
(x锛?
)锛?
锛屾壘鍑?
3锛峹)涓?
x锛?
)鐨勫叧绯伙紟瑙o細
(1)鍥犲紡鍒嗚В锛屽緱x(5x锛?
)锛?
锛?
浜庢槸寰梮锛?
鎴?
x锛?
锛?
锛?
x1锛?
锛寈2锛濓紞35锛?
(2)鍘熸柟绋嬪寲涓?
x(3锛峹)锛?
(x锛?
)锛?
锛?
鍥犲紡鍒嗚В锛屽緱(x锛?
)(锛?
x锛?
)锛?
锛?
浜庢槸寰梮锛?
锛?
鎴栵紞7x锛?
锛?
锛?
x1锛?
锛寈2锛濓紞472锛庨€夋嫨鍚堥€傜殑鏂规硶瑙d笅鍒楁柟绋嬶細
(1)2x2锛?
x锛?
锛?
锛?
(2)(1锛峹)(x锛?
)锛?
x锛?
)(1锛?
x)锛?
鍒嗘瀽锛?
1)棰樺疁鐢ㄥ叕寮忔硶锛?
2)棰樹腑鎵惧埌(1锛峹)涓?
x锛?
)鐨勫叧绯荤敤鍥犲紡鍒嗚В娉曪紱瑙o細
(1)a锛?
锛宐锛濓紞5锛宑锛?
锛?
b2锛?
ac锛?
锛?
)2锛?
脳2脳2锛?
锛?
锛?
x锛?
卤92脳2锛?
卤34锛?
x1锛?
锛寈2锛?
2
(2)鍘熸柟绋嬪寲涓?
1锛峹)(x锛?
)锛?
1锛峹)(1锛?
x)锛?
锛?
鍥犲紡鍒嗚В锛屽緱(1锛峹)(5锛峹)锛?
锛?
鍗?
x锛?
)(x锛?
)锛?
锛?
x锛?
锛?
鎴杧锛?
锛?
锛?
x1锛?
锛寈2锛?
3锛庣敤鍥犲紡鍒嗚В娉曡В涓嬪垪鏂圭▼锛?
(1)10x2锛?
x锛?
锛?
(2)7x(3锛峹)锛?
(x锛?
)锛?
(3)9(x锛?
)2锛?
(x锛?
)2.鍒嗘瀽锛?
1)宸﹁竟锛漻(10x锛?
)锛屽彸杈癸紳0锛?
2)鍏堟妸鍙宠竟鍖栦负0锛?
x(3锛峹)锛?
(x锛?
)锛?
锛屾壘鍑?
3锛峹)涓?
x锛?
)鐨勫叧绯伙紱(3)搴旂敤骞虫柟宸叕寮忥紟瑙o細
(1)鍥犲紡鍒嗚В锛屽緱x(10x锛?
)锛?
锛?
浜庢槸寰梮锛?
鎴?
0x锛?
锛?
锛?
x1锛?
锛寈2锛濓紞310锛?
(2)鍘熸柟绋嬪寲涓?
x(3锛峹)锛?
(x锛?
)锛?
锛?
鍥犲紡鍒嗚В锛屽緱(x锛?
)(锛?
x锛?
)锛?
锛?
浜庢槸寰梮锛?
锛?
鎴栵紞7x锛?
锛?
锛?
x1锛?
锛寈2锛?
锛?
7锛?
(3)鍘熸柟绋嬪寲涓?
(x锛?
)2锛?
(x锛?
)2锛?
锛?
鍥犲紡鍒嗚В锛屽緱[3(x锛?
)锛?
(x锛?
)][3(x锛?
)锛?
(x锛?
)]锛?
锛?
鍗?
5x锛?
)(x锛?
)锛?
锛?
浜庢槸寰?
x锛?
锛?
鎴杧锛?
锛?
锛?
x1锛?
5锛寈2锛?
.4锛庡凡鐭?
a2锛媌2)2锛?
a2锛媌2)锛?
锛?
锛屾眰a2锛媌2鐨勫€硷紟鍒嗘瀽锛氳嫢鎶?
a2锛媌2)鐪嬩綔涓€涓暣浣擄紝鍒欏凡鐭ユ潯浠跺彲浠ョ湅浣滄槸浠?
a2锛媌2)涓烘湭鐭ユ暟鐨勪竴鍏冧簩娆℃柟绋嬶紟瑙o細璁綼2锛媌2锛漻锛屽垯鍘熸柟绋嬪寲涓簒2锛峹锛?
锛?
.a锛?
锛宐锛濓紞1锛宑锛濓紞6锛宐2锛?
ac锛?
2锛?
脳(锛?
)脳1锛?
5锛?
锛?
x锛?
卤252锛屸埓x1锛?
锛寈2锛濓紞2.鍗砤2锛媌2锛?
鎴朼2锛媌2锛濓紞2锛?
鈭礱2锛媌2鈮?
锛屸埓a2锛媌2锛濓紞2涓嶅悎棰樻剰搴旇垗鍘伙紝鍙朼2锛媌2锛?
.鍥涖€佸笀鐢熶簰鍔ㄣ€佽鍫傚皬缁?
鍏堝皬缁勫唴浜ゆ祦鏀惰幏鍜屾劅鎯筹紝鑰屽悗浠ュ皬缁勪负鍗曚綅娲句唬琛ㄨ繘琛屾€荤粨锛庢暀甯堜綔浠ヨˉ鍏咃紟璇惧悗浣滀笟甯冪疆浣滀笟锛氭暀鏉愨€滅粌涔犻2.2鈥濅腑绗?
銆?
銆?
銆?
0棰橈紟鏁欏鍙嶆€?
杩欒妭璇句富瑕佸涔犱簡鐢ㄥ洜寮忓垎瑙f硶瑙d竴鍏冧簩娆℃柟绋嬬殑姒傚康鍙婂叾瑙f硶锛岃В娉曠殑鍩烘湰鎬濊矾鏄皢涓€鍏冧簩娆℃柟绋嬭浆鍖栦负涓€鍏冧竴娆℃柟绋嬶紝鑰岃揪鍒拌繖涓€鐩殑锛屾垜浠富瑕佸埄鐢ㄤ簡鍥犲紡鍒嗚В鈥滈檷娆♀€濓紟鍦ㄤ粖澶╃殑瀛︿範涓紝瑕侀€愭娣卞叆銆侀浼氥€佹帉鎻♀€滆浆鍖栤€濊繖涓€鏁板鎬濇兂鏂规硶锛?
- 配套讲稿:
如PPT文件的首页显示word图标,表示该PPT已包含配套word讲稿。双击word图标可打开word文档。
- 特殊限制:
部分文档作品中含有的国旗、国徽等图片,仅作为作品整体效果示例展示,禁止商用。设计者仅对作品中独创性部分享有著作权。
- 关 键 词:
- 九年级 数学 22 一元 二次方程 解法 教案 新版 湘教版