瀹屾暣鐗堟湰
.
浜屾鍑芥暟鐨勮В鏋愬紡姹傛硶
姹備簩娆″嚱鏁扮殑瑙ｆ瀽寮忚繖绫婚娑夊強闈㈠箍锛?/p>
鐏垫椿鎬уぇ锛?/p>
鎶�宸ф�у己锛?/p>
绗旇�呯粨鍚堣繎鍑犲勾鏉ョ殑涓�?
璇曢锛屾�荤粨鍑哄嚑绉嶈В鏋愬紡鐨勬眰娉曪紝渚涘悓瀛︿滑瀛︿範鏃跺弬鑰冦�?/p>
涓�銆?/p>
涓夌偣鍨?/p>
渚?/p>
1
宸茬煡涓�涓簩娆″嚱鏁板浘璞＄粡杩囷紙
-1
锛?/p>
10
锛?/p>
銆?/p>
锛?/p>
2
锛?/p>
7
锛夊拰锛?/p>
1
锛?/p>
4
锛変笁鐐癸紝閭ｄ箞杩欎釜鍑?
鏁扮殑瑙ｆ瀽寮忔槸
_______
銆?/p>
鍒嗘瀽
宸茬煡浜屾鍑芥暟鍥捐薄涓婄殑涓変釜鐐癸紝鍙鍏惰В鏋愬紡涓?/p>
y=ax
2
+bx+c,
灏嗕笁涓偣鐨勫潗鏍囦唬
鍏ワ紝鏄撳緱
a=2,b=-3,c=5
銆傛晠鎵�姹傚嚱鏁拌В鏋愬紡涓?/p>
y=2x
2
-3x+5.
杩欑鏂规硶鏄皢鍧愭爣浠ｅ叆
y=ax
2
+bx+c
鍚庯紝鎶婇棶棰樺綊缁撲负瑙ｄ竴涓笁鍏冧竴娆℃柟绋嬬粍锛屾眰鍑哄緟瀹氱郴
鏁?/p>
a, b , c,
杩涜�岃幏寰楄В鏋愬紡
y=ax
2
+bx+c.
浜屻�佷氦鐐瑰瀷
渚?/p>
2
宸茬煡鎶涚墿绾?/p>
y=-2x
2
+8x-9
鐨勯《鐐逛负
A
锛岃嫢浜屾鍑芥暟
y=ax
2
+bx+c
鐨勫浘鍍忕粡杩?/p>
A
鐐癸紝
涓斾笌
x
杞翠氦浜?/p>
B
锛?/p>
0
锛?/p>
0
锛?/p>
銆?/p>
C
锛?/p>
3
锛?/p>
0
锛変袱鐐癸紝璇曟眰杩欎釜浜屾鍑芥暟鐨勮В鏋愬紡銆?/p>
鍒嗘瀽
瑕佹眰鐨勪簩娆″嚱鏁扮殑鍥捐薄涓?/p>
x
杞寸殑涓や釜浜ょ偣鍧愭爣锛屽彲璁?/p>
y=ax(x-3),
鍐嶆眰涔?/p>
y=-2x
2
+8x-9
鐨勯《鐐?/p>
A
锛?/p>
2
锛?/p>
-1
锛?/p>
銆傚皢
A
鐐圭殑鍧愭爣浠ｅ叆
y=ax(x-3),
寰楀埌
a=
2
1
鈭?/p>
y=
2
1
x(x-3),
鍗?/p>
y=
x
x
2
3
2
1
2
飥?/p>
.
涓夈�侀《鐐瑰瀷
渚?/p>
3
宸茬煡鎶涚墿绾?/p>
y=ax
2
+bx+c
鐨勯《鐐规槸
A(-1,4)
涓旂粡杩囩偣
(1,2)
姹傚叾瑙ｆ瀽寮忋�?/p>
鍒嗘瀽
姝ょ被棰樺瀷鍙椤剁偣鍧愭爣涓?/p>
(m,k)
锛?/p>
鏁呰В鏋愬紡涓?/p>
y=a(x-m)
2
+k.
鍦ㄦ湰棰樹腑鍙
y=a(x+1)
2
+4.