Number Theory Division Algorithm interesting problem

In summary, the conversation discusses how to show that any integer to the fourth power can be expressed as either 5k or 5k+1, where k is an integer. The participants suggest starting with the fact that all integers can be expressed as either 2x or 2x+1, and then considering the possibilities when raised to the fourth power. They also mention using arithmetic modulo 5 and proof by induction as potential approaches.
  • #1
PsychonautQQ
784
10

Homework Statement


Not actually for homework, but i didn't know where to post this.

Problem: Show that any integer to the fourth power can be expressed as either 5k or 5k+1 where k is an integer.

Homework Equations


None.

The Attempt at a Solution


My starting point is to consider that all integers can be expressed as either:
2x or 2x+1

taking these to the fourth power I arrive at:
16k or 16k + 1

now I'm stuck, any tips? am i even on the right trail here?
 
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  • #2
PsychonautQQ said:
My starting point is to consider that all integers can be expressed as either:
2x or 2x+1

You could start by considering they can be expressed as one of:
5x, 5x+1, 5x+2, 5x+3, 5x+4

If you are familiar with arithmetic modulo 5, you could compute the 4th power of each of the 5 residue classes.
 
  • #3
2x4 = 16k I can understand.
But perhaps you want to reconsider (2x+1)4 = 16k+1. How did you do that ?

On another note: are you familiar with proof by induction ?
 

1. What is the Number Theory Division Algorithm and why is it an interesting problem?

The Number Theory Division Algorithm is a mathematical method for finding the quotient and remainder when dividing two numbers. It is interesting because it is a fundamental concept in number theory and has many applications in fields such as cryptography and computer science.

2. How does the Number Theory Division Algorithm work?

The algorithm involves repeatedly subtracting the divisor from the dividend until the result is less than the divisor. The number of times this process is repeated is the quotient, and the final result is the remainder. This method relies on the fact that any number can be expressed as a multiple of another number plus a remainder.

3. What are some real-world applications of the Number Theory Division Algorithm?

The algorithm is used in cryptography to generate public and private keys for secure communication. It is also used in computer science to efficiently perform operations on large numbers, such as in prime factorization and modular arithmetic.

4. Can the Number Theory Division Algorithm be used for all types of numbers?

No, the algorithm only works for integers. It cannot be used for fractions or irrational numbers.

5. Are there any limitations or drawbacks to the Number Theory Division Algorithm?

One limitation is that it can only be used for division of integers, not decimals or fractions. Additionally, the algorithm can be time-consuming for very large numbers, so more efficient methods may be preferred in some cases.

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