Math, asked by Itzashgirl, 1 month ago

☆show that cube of every positive integer is in the form of 6p, 6 p + 1 6p - 1 60 - 2 ,6 p + 2 ,6p + 3

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Read the question carefully there is no even or odd Integers mentioned!

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Answers

Answered by helper016455
2

Step-by-step explanation:

Using Euclid division algorithm, we know that a=bq+r, 0≤r≤b ----(1)

Let a be any positive integer and b=6.

Then, by Euclid’s algorithm, a=6q+r for some integer q≥0, and r=0,1,2,3,4,5 ,or 0≤r<6.

Therefore, a=6qor6q+1or6q+2or6q+3or6q+4or6q+5

6q+0:6 is divisible by 2, so it is an even number.

6q+1:6 is divisible by 2, but 1 is not divisible by 2 so it is an odd number.

6q+2:6 is divisible by 2, and 2 is divisible by 2 so it is an even number.

6q+3:6 is divisible by 2, but 3 is not divisible by 2 so it is an odd number.

6q+4:6 is divisible by 2, and 4 is divisible by 2 so it is an even number.

6q+5:6 is divisible by 2, but 5 is not divisible by 2 so it is an odd number.

And therefore, any odd integer can be expressed in the form 6q+1or6q+3or6q+5

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Answered by tennetiraj86
3

Step-by-step explanation:

Given :-

A positive integer

To find :-

Show that cube of every positive integer is in the form of 6p, 6 p + 1, 6p - 1 ,6p - 2 ,6 p + 2 ,6p + 3?

Solution:-

We know that

Euclid's Division Algorithm:-

For any two positive integers a and b there exist two positive integers q and r satisfying a = bq+r where 0 ≤ r <b.

Let b = 6 then a = 6q+r -----------(1)

Where , 0≤r<6

The possible values of r = 0,1,2,3,4,5

i) If r = 0 then (1) becomes

=> a = 6q+0

=> a = 6q

On cubing both sides then

=> a³ = (6q)³

=>a³ = 216q³

=> a³ = 6(36q³)

=> a³ = 6p ------------------------------(2)

where p = 36q³

ii) If r = 1 then (1) becomes

=> a = 6q+1

On cubing both sides then

=> a³ = (6q+1)³

=> a³ = 216q³+3(36q²)(1)+3(6q)(1²)+1

=> a³ = 216q³+108q²+18q+1

=> a³ = 6(36q³+18q²+3q)+1

=> a³ = 6p+1 ---------------------------(3)

Where p = 36q³+18q²+3q

iii) If r = 2 then (1) becomes

=> a = 6q+2

On cubing both sides then

=> a³ = (6q+2)³

=> a³ = 216q³+3(36q²)(2)+3(6q)(2²)+2³

=> a³ = 216q³+216q²+72q+8

=> a³ = 216q³+216q²+72q+6+2

=> a³ = 6(36q³+36q²+12q+1)+2

=> a³ = 6p+2 ----------------------------(4)

Where p = 36q³+36q²+12q+1

iv)If r = 3 then (1) becomes

=> a = 6q+3

On cubing both sides then

=> a³ = (6q+3)³

=> a³ = 216q³+3(36q²)(3)+3(6q)(3²)+3³

=> a³ = 216q³+324q²+162q+27

=> a³ = 216q³+324q²+162q+24+3

=> a³ = 6(36q³+54q²+27q+4)+3

=> a³ = 6p+3 ---------------------------(5)

Where p = 36q³+54q²+27q+4

v)If r = 4 then (1) becomes

=> a = 6q+4

On cubing both sides then

=> a³ = (6q+4)³

=> a³ = 216q³+3(36q²)(4)+3(6q)(4²)+4³

=> a³ = 216q³+432q²+204q+64

=> a³ = 216q³+432q²+204q+66-2

=> a³ = 6(36q³+72q²+34q+11)-2

=> a³ = 6p-2 -----------------------------(6)

Where p = 36q³+72q²+34q+11

vi)If r = 5 then (1) becomes

=> a = 6q+5

On cubing both sides then

=> a³ = (6q+5)³

=> a³ = 216q³+3(36q²)(5)+3(6q)(5²)+5³

=> a³ = 216q³+540q²+750q+125

=> a³ = 216q³+540q²+750q+126-1

=> a³ = 6(36q³+90q²+125q+21)-1

=> a³ = 6p-1 ------------------------------(7)

Where p = 36q³+90q²+125q+21

From (2),(3),(4),(5),(6),(7)

The cube of every positive integer is in the form of 6p,6p+1,6p-1,6p-2,6p+2,6p+3

Hence, Proved.

Answer:-

The cube of every positive integer is in the form of 6p, 6 p + 1, 6p - 1 ,6p - 2 ,6 p + 2 ,6p + 3.

Used formulae:-

Euclid's Division Algorithm:-

"For any two positive integers a and b there exist two positive integers q and r satisfying a = bq+r where 0 ≤ r <b".

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