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Lv 5
? asked in Science & MathematicsMathematics · 9 years ago

A problem from Fermat's last theorem?

Consider the equation

a³ + b³ = c³

has no integer solutions according to Fermat (and Andrew Wiles)

can be proven easily if b = a? 2a³ = c³ and (³√ 2)a = c but ³√ 2 is irrational completes the proof.

now take case b≠a; say b = na where b>a without loss of generality so n>1;

get ³√ (n³ +1) = c/a means that there is no integer n where ³√ (n³ +1) is rational.

My question is try to find a number n>1 so that b³ - a³ = c³ exists for integers solution.

³√ (n³ -1) = c/a ... can this be done?

1 Answer

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  • Paula
    Lv 7
    9 years ago
    Favorite Answer

    No. Because:

    b^3 - a^3 = c^3

    => b^3 = c^3 + a^3

    ... which has no positive integer solutions by Fermat's last theorem

    (Need to specify positive integer, because otherwise you can set a=0)

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