Think logically not mathematically [part-22]

How many ordered pairs ( A , B , C ) (A,B,C) exists such that the below equation satisfies and also A , B , C A,B,C are consecutive Natural numbers A 3 + B 3 = C 2 A^3+B^3=C^2


The answer is 1.

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2 solutions

Omkar Kulkarni
Feb 17, 2015

Let the numbers be n 1 , n , n + 1 n-1,n,n+1 .

( n 1 ) 3 + n 3 = ( n + 1 ) 2 \therefore (n-1)^{3}+n^{3}=(n+1)^{2}

n 3 1 3 n 2 + 3 n + n 3 = n 2 + 2 n + 1 n^{3}-1-3n^2+3n+n^{3}=n^{2}+2n+1

2 n 3 4 n 2 + n 2 = 0 2n^{3}-4n^{2}+n-2=0

2 n 2 ( n 2 ) + ( n 2 ) = 0 2n^{2}(n-2)+(n-2)=0

( 2 n 2 + 1 ) ( n 2 ) = 0 (2n^{2}+1)(n-2)=0

n 2 = 0 n = 2 n-2=0\Rightarrow n=2

Hence there is only one ordered triplet satisfying the given equation, ( 1 , 2 , 3 ) (1,2,3) .

Sudoku Subbu
Feb 16, 2015

The exists only one possibilities that is 1 3 + 2 3 = 3 2 1^3+2^3=3^2

How will you prove that there is only one possibility

Vishal S - 6 years, 3 months ago

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Yes you may say if any other possibilty exists dont behave like a proffessor

sudoku subbu - 6 years, 3 months ago

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Please mind your words.This is Brilliant not any playground to extend your words

Vishal S - 6 years, 3 months ago

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@Vishal S what did i do sir? i did not treat you with bad words ! even now iam calling you "sir" sir?

sudoku subbu - 6 years, 3 months ago

Why is it combinatorics?

Nihar Mahajan - 6 years, 2 months ago

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