Hvis a, b > 0, bestem a*b når
[tex](a+b)^4\,=\,2(a^2-b^2)^2[/tex]
og
[tex]a^2+b^2\,=\,30[/tex]
ab
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Klaus Knegg
- Cayley
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- Location: Ålen
[tex](a+b)^4=2(a^2-b^2)^2[/tex]
[tex](a+b)^2 \cdot (a+b)^2 = 2(a+b)^2 \cdot (a-b)^2[/tex]
[tex](a+b)^2=2(a-b)^2[/tex]
[tex]a^2+2ab+b^2=2a^2-4ab+2b^2[/tex]
[tex]0=a^2+b^2-6ab[/tex]
[tex]0=30-6ab[/tex]
[tex]6ab=30 \rightarrow ab=5[/tex]
Ser det greit ut? : )
[tex](a+b)^2 \cdot (a+b)^2 = 2(a+b)^2 \cdot (a-b)^2[/tex]
[tex](a+b)^2=2(a-b)^2[/tex]
[tex]a^2+2ab+b^2=2a^2-4ab+2b^2[/tex]
[tex]0=a^2+b^2-6ab[/tex]
[tex]0=30-6ab[/tex]
[tex]6ab=30 \rightarrow ab=5[/tex]
Ser det greit ut? : )
This sentence is false.
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Vektormannen
- Euler
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Ser ikke noen feil jeg hvertfall 
Elektronikk @ NTNU | nesizer
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Klaus Knegg
- Cayley
- Posts: 92
- Joined: 03/05-2006 17:30
- Location: Ålen
Da satser jeg på det
This sentence is false.
