九年级(下)——二次函数全章教案-新人教[整理]】

26.11234112m22yx1y(cm2)x(Cm)(2)2,,xy;(3),12Om,,x(cm),y(m2)1113x11yx21y=22y=2000(1+x)2=20000x2+40000x+20000(3)y=(60-x-4)(x-2)=-x2+58x-112y=ax2+bx+c(a,b,c,a0).y=ax2+bx+c(a,b,Ca0)(quadraticfuncion)abc21(1)(2)(3)4521233m1x=14x=2-5x=23x=-2222cm4AE=BF=CG=DH=x(cm),EFGHy(cm2),1yxx2x0.250.51.51.75EFGHABEFCGDH1yx2EFGH=ABCD-AEHDE4EFGHEH2(3)42xyxyy20x,y,(1)yx.x(2)x=3,?4526.211234111x-2-101241014-4--1-0--1--4xyxy2.3x2312yy3y4x()x()3(1)(2)(xx)-2-31a21312(2)y=ax2A-2-812B-1-43-61.y=ax2(a0).2.y,3.a0,,;a0,,26.221231234x()x()1234100-202202-22-4223y=a(x+m)2.-m,0,x=-m41y=2(x+3)2y=-3(x-1)2y=-4(x-3)22y=2x2y=2(x+1)2y=-5(x-4)2433m12323x=-m-mkmkmk4341212351226.2312321212=mk1y=ax2+bx+ca0y=ax2+bx+cy=a(x+m)2+k=372221(a0)2x=(3)a0a01123637132x-121-312()14137323712m4m?x1A2B3C1232.311..2..3.,(),,,..:y=ax2+bx+c(a0),?:a,,a,,.,:1.:y=-2x2,x_____0,yxx_____0,yx.x=y____.x____0,y0.0y=-2x20y=2x2yx2.:y=2x2,x_____0,yxx_____0,yx.x=y____.x____0,y03.:y=ax2+bx+c(a0)(1).(2).(3).a0yxyxya0yxyxy4.y=x2+2x,y=x2-2x+1,y=x2-2x+2.(1).x(2).x2+2x=0,x2-2x+1=0?x2-2x+2=0?(3).y=ax2+bx+cxax2+bx+c=0?:(3).y=ax2+bx+cx:,,.y=ax2+bx+cx,y=0x,ax2+bx+c=0.b2-4ac0x0=ax2+bx+cx1x2b2-4ac=0xb2-4ac0x:y=x2-3x+2xAB1x2-3x+2=0y=x2-3x+2xax2+bx+c=0x1x2y=ax2+bx+cAx10Bx2,05.:1:y(2)xyxyx:.:p42.1,2.:1.:12,123426.321231x_____0yxx_____0,yxx=y____2x_____0yxx_____0,yxx=y____11A-30B10C0-2(2)24013x=3,1050x2y=x2-2x-3,234(5)xAByPAPB6xy=0;y0;y0.12y0;xx3y=ax2+bx+c(a0)yxoa0;b0;c0;0y=ax2+bx+c(a0)abcaa0.a0bb0.yb=0b0ycc0.yC=0yc0y0.x=0x0x56a+b+c0a-b+c0abc0b=2ax-11yA1B2C3D426.41123138mx(4-x)ym2,x=2=4(m2)8m1840.01426.4(2)12321(1)(2)281Lx2LLxx2BA26kmABA12kmB5km1(2)tttABABAB===169t2-260t+676s:tABABABS=AB====t0t=169t-2+576576t=S==24km24km2426.4(3)12333200,5()6789101112()480440400360320280240(1)x()yyx(2)(0.1)P47