Math, asked by Anonymous, 1 year ago

the cube of any positive integer is not of the form​

Answers

Answered by Anonymous
8

Answer:

the cube of any positive integer is of the form 9q,or 9q+1or 9q+8....

i hope it's help to you

Answered by ismartnani
2

Answer:

Let a be any positive integer and b = 3

a = 3q + r, where q ≥ 0 and 0 ≤ r < 3

  

Therefore, every number can be represented as these three forms. There are three cases.

Case 1: When a = 3q, 

  

Where m is an integer such that m =   

Case 2: When a = 3q + 1,

a 3 = (3q +1) 3 

a 3 = 27q 3 + 27q 2 + 9q + 1 

a 3 = 9(3q 3 + 3q 2 + q) + 1

a 3 = 9m + 1 

Where m is an integer such that m = (3q 3+ 3q 2 + q) 

Case 3: When a = 3q + 2,

a 3 = (3q +2) 3 

a 3 = 27q 3 + 54q 2 + 36q + 8 

a 3 = 9(3q 3 + 6q 2 + 4q) + 8

a 3 = 9m + 8

Where m is an integer such that m = (3q 3+ 6q 2 + 4q) 

Therefore, the cube of any positive integer is of the form 9m, 9m + 1, or 9m + 8.

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