Divisors of a Number: n2+1 for 4k+1 Divisibility

  • Thread starter jeedoubts
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There is some info about divisibility rules with 7, 11 and 13. For example, with 7 you can take the last digit, multiply by 2, 3, 1 and add to the rest. So, if you have 7^2, you can remove all digits but the last, and repeat 2 times, until you get 49. The same with 11: you can take the first, subtract the rest, and so on... In summary, if n1 is even, the total number of divisors of the form of 4k+1 must be divisible by n2+1.
  • #1
jeedoubts
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1. Homework Statement
let N= (7^n1)(9^n2)(11^n1)
if n1 is even,then the total number of divisors of the form of 4k+1 must be divisible by?

correct answer is n2+1

3. The Attempt at a Solution
total number of divisors = (n1+1)(n2+1)(n1+1)
 
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  • #2
jeedoubts said:
1. Homework Statement
let N= (7^n1)(9^n2)(11^n1)
if n1 is even,then the total number of divisors of the form of 4k+1 must be divisible by?

correct answer is n2+1

3. The Attempt at a Solution
total number of divisors = (n1+1)(n2+1)(n1+1)

can anybody please help me uot in this question?
 
  • #3
jeedoubts said:
1. Homework Statement
let N= (7^n1)(9^n2)(11^n1)
if n1 is even,then the total number of divisors of the form of 4k+1 must be divisible by?

correct answer is n2+1

3. The Attempt at a Solution
total number of divisors = (n1+1)(n2+1)(n1+1)

can anybody please help me out in this question?
 
  • #4
Hm... I don't have the solution, but can give some idea: The factor decomposition is funny, using 9 instead of 3. Anyway, put it like 9^n2 (7*11)^n1. Now get numbers of the form 4k+1: 1, 5, 9, 13, 17, 21, 25... 81... So, you see: powers of 9 are of the form 4k+1. You have to prove that no number of that form can be a multiple of 7 or 11.
 

What does the term "divisors" mean in this context?

In mathematics, divisors are numbers that can divide another number evenly without leaving a remainder. For example, the divisors of 10 are 1, 2, 5, and 10.

What does the formula n2+1 represent?

The formula n2+1 represents a number that is one more than the square of another number. For example, if n=3, then n2+1 would equal 10.

What does the notation 4k+1 mean?

The notation 4k+1 represents a number that is one more than a multiple of 4. For example, if k=2, then 4k+1 would equal 9.

How do you determine if n2+1 is divisible by 4k+1?

In order for n2+1 to be divisible by 4k+1, both n2 and 1 must be divisible by 4k+1. This means that n2+1 must have a remainder of 0 when divided by 4k+1.

What is the significance of studying "Divisors of a Number: n2+1 for 4k+1 Divisibility"?

Studying this topic is important for understanding the properties and patterns of numbers. It also has practical applications in cryptography and number theory. Additionally, it can help develop problem-solving and critical thinking skills.

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