Предмет: Алгебра, автор: asimx

Решить неравенство  frac{1-3^{ x^{2} +2x-3}}{x^{2} +2x-3}  leq 0

Ответы

Автор ответа: 90misha90
0
 frac{1-3^{x^2+2x-3}}{x^2+2x-3} leq 0
let's t=x^2+2x-3

 frac{1-3^t}{t} leq 0;

We have three possible cases:

first:

 left { {{frac{1-3^t}{t} leq 0|*t} atop {t textgreater  0}} right. ; 
 left { {{1-3^t leq 0} atop {t textgreater  0}} right. ; 
 left { {{-3^t leq -1} atop {t textgreater  0}} right. ; 
 left { {{3^t geq 1} atop {t textgreater  0}} right. ; 
 left { {{3^t geq 3^0} atop {t textgreater  0}} right. ; 
 left { {{t geq 0} atop {t textgreater  0}} right. ; 
t textgreater  0

t=x^2+2x-3 textgreater  0

x^2+3x-x-3 textgreater  0

x(x+3)-(x+3) textgreater  0

(x-1)(x+3) textgreater  0

[x-(1)]*[x-(-3)] textgreater  0

xin (-infty;-3)cup(1;+infty)

second:

 left { {{frac{1-3^t}{t} leq 0|*t} atop {t textless  0}} right. ;
 left { {{1-3^t geq 0} atop {t textless  0}} right. ;
 left { {{-3^t geq -1} atop {t textless  0}} right. ;
 left { {{3^t leq 1} atop {t textless  0}} right. ;
 left { {{3^t leq 3^0} atop {t textless  0}} right. ;
 left { {{t leq 0} atop {t textless  0}} right. ;
t textless  0

t=x^2+2x-3  textless  0

[x-(1)]*[x-(-3)] textless  0

xin (-3;1)

third:

 left { {{ frac{1-3^t}{t}  leq 0} atop {t=0}} right. ;
 left { {{ frac{1-3^0}{0}  leq 0} atop {t=0}} right. ;
 left { {{ frac{0}{0}  leq 0} atop {t=0}} right.

The system of inequalities behind have not sense due to its first inequality.
----------------------------------
So, we have: tin (-infty;0)cup(0;+infty)

and x^2+2x-3 neq 0;

(x-1)(x+3) neq 0

xin (-infty;-3)cup(-3;1)cup(1;+infty)

Answer: (-infty;-3)cup(-3;1)cup(1;+infty)
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