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濂嬫枟娌℃湁缁堢偣浠讳綍鏃跺�欓兘鏄竴涓捣鐐?/p>
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淇¤揪
鍒濅腑鏁板璇曞嵎
22.1.2
浜屾鍑芥暟
y=ax
2
鐨勫浘璞″拰鎬ц川
瑕佺偣鎰熺煡
1
浜屾鍑芥暟
y=ax
2
鐨勫浘璞℃槸
____
锛屽绉拌酱鏄?/p>
____
锛岄《鐐规槸
____.
褰?/p>
a>0
鏃讹紝鎶涚墿绾跨殑寮�鍙ｅ悜
____
锛岄《鐐规槸
鎶涚墿绾跨殑鏈�
____
鐐癸紱褰?/p>
a<0
鏃讹紝鎶涚墿绾跨殑寮�鍙ｅ悜
____
锛岄《鐐规槸鎶涚墿绾跨殑鏈�
____
鐐?/p>
.|a|
瓒婂ぇ锛屾姏鐗╃嚎鐨勫紑鍙?/p>
____.
棰勪範缁冧範
1-1
鎶涚墿绾?/p>
y=-x
2
鐨勫紑鍙ｆ柟鍚?/p>
____
锛岄《鐐瑰潗鏍囨槸
____
锛屽绉拌酱鏄?/p>
____.
瑕佺偣鎰熺煡
2
鍦ㄤ簩娆″嚱鏁?/p>
y=ax
2
(a
鈮?/p>
0)
鍥捐薄涓紝鈶犲綋
a>0
锛?/p>
x>0
鏃讹紝
y
闅?/p>
x
澧炲ぇ鑰?/p>
____
锛?/p>
x<0
鏃讹紝
y
闅?/p>
x
澧炲ぇ鑰?/p>
____
锛?/p>
褰?/p>
x=0
鏃讹紝
y
鍙栨渶
____
鍊兼槸
0
锛涒憽褰?/p>
a<0
锛?/p>
x>0
鏃讹紝
y
闅?/p>
x
澧炲ぇ鑰?/p>
____
锛?/p>
x<0
鏃讹紝
y
闅?/p>
x
澧炲ぇ鑰?/p>
____
锛屽綋
x=0
鏃讹紝
y
鍙?/p>
鏈�
____
鍊兼槸
0.
棰勪範缁冧範
2-1
宸茬煡
A(-1,y
1
),B(-2,y
2
)
閮藉湪鎶涚墿绾?/p>
y=3x
2
涓婏紝鍒?/p>
y
1
銆?/p>
y
2
涔嬮棿鐨勫ぇ灏忓叧绯绘槸
( )
A.y
1
>y
2
B.y
1
=y
2
C.y
1
<y
2
D.
澶у皬鍏崇郴涓嶈兘纭畾
鐭ヨ瘑鐐?/p>
1
浜屾鍑芥暟
y=ax
2
鐨勫浘璞?/p>
1.
涓嬪垪鍚勭偣锛?/p>
(-1
锛?/p>
2)
锛?/p>
(-1
锛?/p>
-2)
锛?/p>
(-2
锛?/p>
-4)
锛?/p>
(-2
锛?/p>
4)
锛屽叾涓湪浜屾鍑芥暟
y=-2x
2
鐨勫浘璞′笂鐨勬槸
____.
2.
(
涓芥按涓�?/p>
)
鍐欏嚭鍥捐薄缁忚繃鐐?/p>
(-1
锛?/p>
1)
鐨勪竴涓簩娆″嚱鏁拌В鏋愬紡鏄?/p>
____.
3.
宸茬煡浜屾鍑芥暟
y=ax
2
鐨勫浘璞＄粡杩囩偣
A(-1
锛?/p>
-
2
1
).
(1)
姹傝繖涓簩娆″嚱鏁扮殑瑙ｆ瀽寮忓苟鐢诲嚭鍏跺浘璞★紱
(2)
璇疯鍑鸿繖涓簩娆″嚱鏁扮殑椤剁偣鍧愭爣銆佸绉拌酱
.
鐭ヨ瘑鐐?/p>
2
浜屾鍑芥暟
y=ax
2
鐨勬�ц川
4.
(
姣曡妭涓�?/p>
)
鎶涚墿绾?/p>
y=2x
2
锛?/p>
y=-2x
2
锛?/p>
y=
2
1
x
2
鐨勫叡鍚屾�ц川鏄?/p>
( )
A.
寮�鍙ｅ悜涓?/p>
B.
瀵圭О杞存槸
y
杞?/p>
C.
閮芥湁鏈�楂樼偣
D.y
闅?/p>
x
鐨勫澶ц�屽澶?/p>
5.
鍏充簬鍑芥暟
y=3x
2
鐨勬�ц川琛ㄨ堪姝ｇ‘鐨勪竴椤规槸
( )
A.
鏃犺
x
涓轰换浣曞疄鏁帮紝
y
鐨勫�兼�讳负姝?/p>
B.
褰?/p>
x
鍊煎澶ф椂锛?/p>
y
鐨勫�间篃澧炲ぇ
C.
瀹冪殑鍥捐薄鍏充簬
y
杞村绉?/p>
D.
瀹冪殑鍥捐薄鍦ㄧ涓�銆佷笁璞￠檺鍐?/p>
6.
宸茬煡鐐?/p>
(-1
锛?/p>
y
1
)
锛?/p>
(2
锛?/p>
y
2
)
锛?/p>
(-3
锛?/p>
y
3
)
閮藉湪鍑芥暟
y=x
2
鐨勫浘璞′笂锛屽垯
( )
A.y
1
<y
2
<y
3
B.y
1
<y
3
<y
2
C.y
3
<y
2
<y
1
D.y
2
<y
1
<y
3
7.
宸茬煡浜屾鍑芥暟
y=(m-2)x
2
鐨勫浘璞″紑鍙ｅ悜涓嬶紝鍒?/p>
m
鐨勫彇鍊艰寖鍥存槸
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8.
涓嬪垪鍥涗釜浜屾鍑芥暟锛氣憼
y=x
2
锛屸憽
y=-2x
2
锛屸憿
y=
2
1
x
2
锛屸懀
y=3x
2
锛屽叾涓姏鐗╃嚎寮�鍙ｄ粠澶у埌灏忕殑鎺掑垪椤哄簭鏄?/p>
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