求函数y=2x² x分之3,(x>0)的最小值-搜答案-神马作文网

-5/2≤y＜2y=[2(x^2+2x+3)-9]/(x^2+2x+3)=2-9/(x^2+2x+3)=2-9/[(x+1)^2+2]以后的就自己算了

不等2

y=(3x+2)/(x-2)=[3(x-2)+8]/(x-2)=3+8/(x-2)由于8/(x-2)不=0,则y不=3+0=3即值域是(-无穷,3)U(3,+无穷)

y=x-2分之根号3x+2x≠2且x≥-2/3y=1-根号x分之1x＞0

y'=-2/x^2-6/x^3+12/x^4

2/3

因为X+2/X-Y=2所以X=2Y+2将X=2Y+2代入X+Y/3（X-Y）-（X-Y）/2（X+Y）=（3Y+2）/3（2Y+2-Y）-（2Y+2-Y）/2（3Y+2）接下来自己算

答：x>1,x-1>0所以：y=2x+1/(x-1)y=2(x-1)+1/(x-1)+2y>=2√[2(x-1)*1/(x-1)]+2y>=2√2+2当且仅当2(x-1)=1/(x-1)即x-1=√2

y=(5x+3)/(2x-3)=5/2+21/(4x-6)由于21/(4x-6)!=0所以值域(-无穷,5/2)U(5/2,正无穷)

y=(1-x)/(2x+3)y(2x+3)=1-x(2y+1)x=1-3y所以x=(1-3y)/(2y+1),当2y+1不=0时成立.即Y不=-1/2.所以,值域是(-无穷,-1/2)U(-1/2,+

x+y分之x-y=2求x+y分之3x-3y减x-y分之2(x+y)的值x+y分之x-y=2x-y=2(x+y)(x+y)分之(3x-3y)-(x-y)分之2(x+y)的值x+y分之3x-3y=(x+y

x+y分之x-y=2x-y=2(x+y)求x+y分之3x-3y=(x+y)分之3(x-y)=(x+y)分之6(x-y)=6-x-y分之2(x+y)=-(x+y)分之2(x+y)=-2

求函数y=2X^2-3X+1分之1的值域应先求Y=2X^2-3X+1的值域Y=2X^2-3X+1=2（X-3/4)^2-1/8因为2（X-3/4)^2大于等于0所以2（X-3/4)^2-1/8大于等于

x-3在哪个的下面?

函数y=根号2x-3分之x+1有意义,则2x-3分之x+1≥0,则(2x-3)(x+1)≥0且2x-3≠0则x﹥3/2或x≤-1所以函数y=根号2x-3分之x+1的定义域为：x>3/2或x≤-1

1、定义域：3^(2x-1)-1/9>=03^(2x-1)>=1/9=3^(-2)2x-1>=-2x>=-1/2值域：y>=02、y=(1/2)^(x^2-6x+17)=(1/2)^[(x-3）^2+

f(x)=(x+3)/(x-1)=1+[4/(x-1)],所以值域为{y|y不等于1}y=根号x²+x+1=根号[(x+1/2)^2+3/4]大于等于根号3/4即值域为{y|y大于等于(根号

y=(x+1)分之[(x+1)²＋2]=(x+1)+(x+1)分之2x+1＞0y≥2√(x+1)·(x+1)分之2=2√2x+1<0y≤-2√(x+1)·(x+1)分之2=-2√2所以

y=2x+3x^(-2/3)求函数的极值令y′=2-2x^(-5/3)=0得x^(5/3)=1,故得驻点x=1y″=(10/3)x^(-8/3),y″(1)=10/3>0,故x=1是极小点,miny=

x>2→x-2>0,故依基本不等式得y＝(x^2-3x+3)/(x-2)＝[(x-2)+1/(x-2)]+1≥2√[(x-2)·1/(x-2)]+1＝3.∴x-2＝1/(x-2),即x＝3时,所求最小