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Hva gjør jeg galt?

Posted: 26/10-2012 21:30
by MrHomme
Vis at [tex]f(x)=3x-x^{1,5}[/tex] kan skrives som [tex]x(3-\sqrt{x})[/tex]


Jeg får det til å bli


[tex]f(x)=3x-x^{\frac32}[/tex]

som blir


[tex]x(3-\sqrt{x^2})[/tex]

?

Posted: 26/10-2012 21:33
by Nebuchadnezzar
[tex]a^b \cdot a^d = a^{b+d}[/tex] mens [tex]a^b \cdot a^d \, \neq \, a^{bd}[/tex]

[tex]x^{3/2} \,=\, x^{1 + 1/2} \,=\, \ldots[/tex]

Posted: 26/10-2012 21:33
by Fibonacci92
[tex]x^{\frac{3}{2}} = {x^{1 + \frac{1}{2}} [/tex]

Posted: 26/10-2012 21:34
by Aleks855
[tex]x^{1.5}=x^{\frac32} =x^{1+\frac12}=x\cdot \sqrt x[/tex]

Posted: 26/10-2012 21:44
by MrHomme
takker :)