数学爱好者的请进!不等式2^(x -3 /x +1 )

来源:学生作业帮助网 编辑:作业帮 时间:2024/05/02 07:22:04
数学爱好者的请进!不等式2^(x -3 /x +1 )

数学爱好者的请进!不等式2^(x -3 /x +1 )
数学爱好者的请进!
不等式2^(x -3 /x +1 )

数学爱好者的请进!不等式2^(x -3 /x +1 )
因为二分之一等于二的负一次方
而指数函数2的x次方是单调递增函数
所以x -3 /x +1 ≤-1
所以当x大于0时,x²+2x-3≤0(x≠0)
(x+3)(x-1)≤0,-3≤x≤1,所以3≤x≤1且x≠0.
当x<0时,x -3 /x +1 ≥-1,此时x≤-3或者x≥1,所以x≤-3.
综上所述,得到(负无穷,-3]U(0,1]

同时两边取对数,可得x-3/x+1=<-1,整理得,x-3/x+2=<0(x不等于0)
当x>0时,整理得,(x-1)(x+3)=<0,解得,-3=同理,x<0时,解得,x=<-3.

2^(x-3)/(x+1)≤1/2
2^(x-3)/(x+1)≤2^(-1)
2>1
(x-3)/(x+1)≤-1
(x-3)/(x+1)+1≤0
(x-3+x+1)/(x+1)≤0
(x-1)/(x+1)≤0
(x-1)(x+1)≤0
-1

2^(x-3)/(x+1)≤1/2
2^(x-3)/(x+1)≤2^(-1)
2>1
所以
(x-3)/(x+1)≤-1
(x-3)/(x+1)+1≤0
(x-3+x+1)/(x+1)≤0
(x-1)/(x+1)≤0
(x-1)(x+1)≤0
-1