二次函數(shù)的解析式的三種形式課件

拋物線的解析式駛向勝利的彼岸1

拋物線的解析式駛向勝利的彼岸1拋物線的解析式駛向勝利的彼岸一般式：y=ax2+bx+c頂點(diǎn)對(duì)稱軸2

拋物線的解析式駛向勝利的彼岸一般式：y=ax2+bx+c頂點(diǎn)拋物線的解析式駛向勝利的彼岸頂點(diǎn)式：y=a(x-h)2+k(h,k)直線:x=h

頂點(diǎn)對(duì)稱軸h(h,k)3

拋物線的解析式駛向勝利的彼岸頂點(diǎn)式：y=a(x-h)2+k(拋物線的解析式駛向勝利的彼岸交點(diǎn)式：y=a(x-x1)(x-x2)對(duì)稱軸與x軸交于(x1,0)(x2,0)(x1,0)(x2,0)4

拋物線的解析式駛向勝利的彼岸交點(diǎn)式：y=a(x-x1)(x-畫出下列二次函數(shù)的示意圖，并指出它的對(duì)稱軸，頂點(diǎn)坐標(biāo),與y軸的交點(diǎn)。y＝x2-3x-51.5對(duì)稱軸：頂點(diǎn):與y軸的交點(diǎn):(0,-5)(0,-5)5

畫出下列二次函數(shù)的示意圖，并指出它的對(duì)稱軸，頂點(diǎn)坐標(biāo),與y軸y＝0.5(x-1)(x+3)-1對(duì)稱軸：頂點(diǎn):與y軸的交點(diǎn):(0,-1.5)(-3,0)(1,0)(0,-1.5)(-1,-2)6

y＝0.5(x-1)(x+3)-1對(duì)稱軸：頂點(diǎn):與y軸的交點(diǎn)y＝-2(x-1)2-51對(duì)稱軸：頂點(diǎn):與y軸的交點(diǎn):(0,-7)(0,-7)7

y＝-2(x-1)2-51對(duì)稱軸：頂點(diǎn):與y軸的交點(diǎn):(0,y＝3(x+1)(x+3)-2對(duì)稱軸：頂點(diǎn):與y軸的交點(diǎn):(0,9)(-3,0)(-1,0)(0,9)(-2,-3)直線x=-28

y＝3(x+1)(x+3)-2對(duì)稱軸：頂點(diǎn):與y軸的交點(diǎn):(y＝2x2+5對(duì)稱軸：頂點(diǎn):與y軸的交點(diǎn):(0,5)(0,5)直線x=0(即y軸)(0,5)9

y＝2x2+5對(duì)稱軸：頂點(diǎn):與y軸的交點(diǎn):(0,5)(0,5y＝-2(x+2)(x-3)0.5對(duì)稱軸：頂點(diǎn):與y軸的交點(diǎn):(0,12)(-2,0)(3,0)(0,12)直線x=0.510

y＝-2(x+2)(x-3)0.5對(duì)稱軸：頂點(diǎn):與y軸的交點(diǎn)y＝2(x+1)2-1對(duì)稱軸：頂點(diǎn):與y軸的交點(diǎn):(0,2)(0,2)(-1,0)直線x=-111

y＝2(x+1)2-1對(duì)稱軸：頂點(diǎn):與y軸的交點(diǎn):(0,2)y＝-2(x-1)(x-3)2對(duì)稱軸：頂點(diǎn):與y軸的交點(diǎn):(0,-6)(3,0)(1,0)(0,-6)(2,2)直線x=212

y＝-2(x-1)(x-3)2對(duì)稱軸：頂點(diǎn):與y軸的交點(diǎn):(y＝-3(x-3)23對(duì)稱軸：頂點(diǎn):與y軸的交點(diǎn):(0,-27)(3,0)(0,-27)(3,0)直線x=313

y＝-3(x-3)23對(duì)稱軸：頂點(diǎn):與y軸的交點(diǎn):(0,-2y＝-(x+3)2+1-3對(duì)稱軸：頂點(diǎn):與y軸的交點(diǎn):(0,-8)(-3,1)(0,-8)(-3,1)直線x=-314

y＝-(x+3)2+1-3對(duì)稱軸：頂點(diǎn):與y軸的交點(diǎn):(0,y＝-2(x+2)(x-4)1對(duì)稱軸：頂點(diǎn):與y軸的交點(diǎn):(0,16)(4,0)(-2,0)(0,16)(1,18)直線x=115

y＝-2(x+2)(x-4)1對(duì)稱軸：頂點(diǎn):與y軸的交點(diǎn):(駛向勝利的彼岸

1.已知拋物線y=ax2+bx+c的對(duì)稱軸為x=2，且經(jīng)過(guò)點(diǎn)(1，4)和點(diǎn)(5，0)，則該拋物線的解析式為.16

駛向勝利的彼岸1.已知拋物線y=ax2+bx+c的對(duì)稱軸2.求滿足下列條件的二次函數(shù)解析式：（1）二次函數(shù)的圖像與x軸交于點(diǎn)A(2,0),B(4,0),且圖像過(guò)點(diǎn)C(1,6)（2）二次函數(shù)當(dāng)x=1時(shí)有最大值y=4,且x=0時(shí)

y=0（3）二次函數(shù)的圖像可由函數(shù)y=ax2-1的圖像向左平移2個(gè)單位得到，且過(guò)點(diǎn)M(-1,-3)17

2.求滿足下列條件的二次函數(shù)解析式：17駛向勝利的彼岸已知拋物線,點(diǎn)A(-1,y1),B(1,y2),C(2,y3)在這條拋物線上，比較y1，y2，y3的大小18

駛向勝利的彼岸已知拋物線,18已知拋物線,點(diǎn)A(-1,y1),B(1,y2),C(2,y3)在這條拋物線上，比較y1，y2，y3的大小(m≠0)駛向勝利的彼岸19

已知拋物線,(m≠0)駛向勝利的彼岸19已知拋物線y=ax2+bx+c的稱軸是:直線x=1點(diǎn)A(-1,y1),B(1,y2),C(2,y3)在這條拋物線上，比較y1，y2，y3的大小20

已知拋物線y=ax2+bx+c的稱軸是:直線x=120如圖是拋物線y=ax2+bx+c-1試判斷:a

0,b0,c

0,a+b+c

0,a-b+c

0,2a-b

0,2a+b

0,駛向勝利的彼岸21

如圖是拋物線y=ax2+bx+c-1試判斷:駛向勝利的彼岸2如圖是拋物線y=ax2+bx+c1試判斷:a

0,b0,c

0,a+b+c

0,a-b+c

0,b2-4ac

0,2a+b

0,駛向勝利的彼岸22

如圖是拋物線y=ax2+bx+c1試判斷:駛向勝利的彼岸22如圖是拋物線y=ax2+bx+c1試判斷:a

0,b0,c

0,a+b+c

0,4a-2b+c

0b2-4ac

0,2a+b

0,2a-b

0,23

如圖是拋物線y=ax2+bx+c1試判斷:23如圖是拋物線y=ax2+bx+c1試判斷:ac

0,A+b+c

0,b2-4ac

0,2a+b

0,

4a+2b+c

c

24

如圖是拋物線y=ax2+bx+c1試判斷:24如圖是拋物線y=ax2+bx+c試判斷:a

0,b0,c

0,a+b+c

0,4a-2b+c

0b2-4ac

0,25

如圖是拋物線y=ax2+bx+c試判斷:25