Løs ulikhetene ved regning
Lagt inn: 30/10-2008 15:14
[tex]\frac{x^2 + x -2}{4 - x^2}[/tex] >_ -1
[tex]\frac{x^2 + x -2}{4 - x^2}[/tex] + 1 >_ 0
Fellesnevner = [tex](2-x)(2+x)[/tex]
ABC_formelen gir: [tex]\frac{(x-1)(x+2)}{(2-x)(2+x)[/tex] + [tex]\frac{(2-x)(2+x)}{(2-x)(2+x)[/tex] >_ 0
[tex]\frac{(x-1)(x+2)(2-x)(2+x)}{(2-x)(2+x)[/tex] >_ 0
Tegner fortegnsskjema for [tex](x-1)(x+2)(2-x)[/tex]
(x-1) -------------(-2)-----------------1____________2_____________
(x+2) -------------(-2)_______________________________________
(2-x) _________(-2)_____________1____________2-----------------
Brøk + - + -
L {<--,-2} U {1,2}
Hvorfor er dette feil?
[tex]\frac{x^2 + x -2}{4 - x^2}[/tex] + 1 >_ 0
Fellesnevner = [tex](2-x)(2+x)[/tex]
ABC_formelen gir: [tex]\frac{(x-1)(x+2)}{(2-x)(2+x)[/tex] + [tex]\frac{(2-x)(2+x)}{(2-x)(2+x)[/tex] >_ 0
[tex]\frac{(x-1)(x+2)(2-x)(2+x)}{(2-x)(2+x)[/tex] >_ 0
Tegner fortegnsskjema for [tex](x-1)(x+2)(2-x)[/tex]
(x-1) -------------(-2)-----------------1____________2_____________
(x+2) -------------(-2)_______________________________________
(2-x) _________(-2)_____________1____________2-----------------
Brøk + - + -
L {<--,-2} U {1,2}
Hvorfor er dette feil?