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ǰλãҳ>>"y6s>o8>>

"y6s>o8

X,YƫҪF(X,Y)= 15E ^ 3* E ^-5Y Ҳ

١߶κy=ax2+bx+c(a>0)M(-1,2)͵N(1,-2), 2=a?b+c ?2=a+b+c ,b=-2.ʸѡȷ.ڷһ:߶κy=ax2+bx+c,a>0öκͼ󿪿ϡߵM(-1,2)͵N(1,-2),ֱMNĽʽΪy-2=2?(?2) ?1?1 [x?(?1)]

κy=ax 2 +bx+c(a0)ͼͼʾ,нȷ A.a>0 B.-1<x<3ʱ,y>0 C.c<0 D.x1ʱ,yx : 0 𰸶 : ܸȤ 1ҹ

:x0y'=5/(25x)>0Ϊx=0ΪСֵy=6

f(x)=y=ax2+ax+c =a(x+1/2)^2+c-a/4 xڡ0,1ʱСֵ1-a f(0)=1-a ༴c=1-a a2-4ac =a^2-4a(1-a) =5a^2-4a =5(a-2/5)^2-4/5 -4/5

a>0ʱ,߷̵x2=-1 a y,p=1 2a ཹΪ (0,-1 4a ).aѡ:b.

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