{y+2z=1 2x-3y-4z=-3 3x-2z=5解方程{y+2z=1 2x-3y-4z=-3 3x-2z=5

来源：学生作业帮助网编辑：六六作业网时间：2024/12/20 08:20:51

{y+2z=12x-3y-4z=-33x-2z=5解方程{y+2z=12x-3y-4z=-33x-2z=5{y+2z=12x-3y-4z=-33x-2z=5解方程{y+2z=12x-3y-4z=-33

{y+2z=1 2x-3y-4z=-3 3x-2z=5解方程{y+2z=1 2x-3y-4z=-3 3x-2z=5
{y+2z=1 2x-3y-4z=-3 3x-2z=5
解方程{y+2z=1 2x-3y-4z=-3 3x-2z=5

{y+2z=1 2x-3y-4z=-3 3x-2z=5解方程{y+2z=1 2x-3y-4z=-3 3x-2z=5
y+2z=1 (1)
2x-3y-4z=-3 (2)
3x-2z=5 (3)
由(1)
y=1-2z
由(3)
x=(5+2z)/3
代入(2)
(10+4z)/3-3(1-2z)-4z=-3
10+4z-9+18z-12z=-9
10z=-10
z=-1
y=1-2z=3
x=1

全部展开

y=(a^x+b^x)^(3/x)
lny=3/x*ln(a^x+b^x)=3ln(a^x+b^x)/x
这是∞/∞,可以用洛必达法则
分子求导=[3/(a^x+b^x)]*(a^x*lna+b^x*lnb)
分母求导=1
所以=3*(a^x*lna+b^x*lnb)/(a^x+b^x)
若|a|<|b|
则上下除以b^x
=3[(a/b)^x*lna+lnb]/[(a/b)^x+1]
此时(a/b)^x趋于0
所以lny极限=3lnb
同理
若 |a|>|b|，则lny极限=3lna
综上
|a|<|b|,极限=e^(3lnb)
|b|<|a|,极限=e^(3lna)

收起

x+2y=3x+2z=4y+z 求x:y:z x+y/2=z+x/3=y+z/4 x+y+z=27 x+y+z=6 x+2y+3z=14 y+1=z 试证明(x+y-2z)+(y+z-2x)+(z+x-2y)=3(x+y-2z)(y+z-2x)(z+x-2y) 已知(x+y)(x+z)=x,(y+z)(y+x)=2y,(z+x)(z+y)=3z,求x,y,z 已知实数x y z满足x/(x+1)=y/(y+2)=z/(z+3)=(x+y+z)/3,求x+y+z的值已知实数x y z满足x/(x+1)=y/(y+2)=z/(z+3)=(x+y+z)/3,求x+y+z的值 x=y/z=z/3,x+y+z ＝12,求2x+3y+4z是多少, 若|x+3|+|y-2|+|2×z+1|=0求(x×z-y×z)(y-x+z)的值 4x+y+z=-3 2x+3y-4z=-10 x+2y-z=-1 x-y-z=1 2x+y-3z=4 3x-2y-z=-1 x+y+z=2 4x+2y+z=4 2x+3y+z=1 x+y-z=6 x-3y+2z=1 3x+2y-z=4 阿 x+y-z=6,x-3y+2z=1,3x+2y-z=4 x+y+z=-5,3x+y+z=1,4x+3y+2z=-2快 3x+2y+z=4 x+y+z=10 2x+3y-z=1 x+y-z=6 x-3y+2z=1 3x+2y-z=4 3X+Y+Z=0,2X-Y+3Z=1,X+2Y-Z=4