A= 7/ - (x2 - 10x +25) +28
A=7/ - (x - 5)2 +28
xét - (x - 5)2 +28 <= 28 dấu = xảy ra khi x - 5 = 0 <=> x=5 . suy ra MIN A = 7/28 = 1/4
Vậy gtnn của A = 1/4 khi x=5
tim GTLN hoac GTNN cua bthuc
a) A=x2-6x+11
B=2x2+10x-1
c) 5x-x2
Tim GTNN cua bieu thuc :
a) A = 11 - 10x -x2
b) B = / x - 4 / . ( 2 - / x - 4 / )
P/s : / la tri tuyet doi nha :)
bai 1:tim GTNN cua bieu thuc
A=x2+3x+7
B=(x-2)(x-5)(x2-7x-10)
bai 2:tim GTLN cua bieu thuc
A=11-10x-x2
B=[x-4](2-[x-4])
bai 3:tim x,y sao cho
A=2x2+9y2-6xy-6x-12y+2016 co GTNN
B=-x2+2xy-4y2+2x+10y-8 co GTLN
bai 4 :
a)cho x+y=3;x2+y2=5.tinh x3+y3
b)cho x-y=5;x2+y2=15.tinh x3-y3
1 tim gtln hoac gtnn cua bt
B=x2-4xy+5y2+10x-22y+28
tim GTNN cua: 3*x^2+y^2-2*x*y-7
Tim GTNN cua A=\(\frac{7}{x^2-x+2}\)
tim GTNN cua A= x^2-3/(x-2)^2
Cho x+y=z=3;\(A=x^2+y^2+z^2;B=xy+yz+xz\) a) C/M:\(A\ge B\) b) tim GTNN cua A c)tim GTLN cua B d) timf GTNN cua A+B
Tim GTNN hoac GTLN cua:
\(\frac{5x^2}{10x^2+1}\)
