Modulo and congruencies in class

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In summary, the conversation is about learning about modulo and congruencies, and seeking help with various problems involving finding a complete residue system modulo 11 consisting of odd numbers, proving a congruence relationship for 7^n and 1+6n (mod 36), and finding the least residue of (n-)! mod n for several values of n. The conversation also includes suggestions for using induction and the binomial theorem to solve the problems.
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i am learning about modulo and congruencies in class and i am seeking some help.

i need to find a complete residue system mod 11 consisting of odds only.

show that every pos int. n, 7^n congruent to 1+6n (mod36)

find the least residue of (n-)! mod n for several values of n. find a rule but no need for a proof.

here is what i know so far...

with the least residue problem, i know that a=mq+r w/ 0<=r<1 then r is the least residue, so it is like the remainder correct? anyone offer further advise to help w/ this?

to find out the conplete resideu system of mod 11 means that m divides (a-b) where a and b are congruent to each other. any other help?

the second problem i really don't know how to do but would like help! please. :cry:
 
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show that every pos int. n, 7^n congruent to 1+6n (mod36)

Try induction. Or maybe you could write 7^n as (1 + 6)^n and expand it with the binomial theorem...

i need to find a complete residue system mod 11 consisting of odds only.

So you need to 10 find odd integers that are congruent to 0, 1, ..., 10 modulo 11. The first one is simple, since 11 = 0 (mod 11). The numbers which are congruent to 1 mod 11, are 1 more than a multiple of 11, i.e they are of the form 1 + 11k. Should be easy from there.
 
  • #3
oooo thanks muzza! i should use the weak form of induction, that should take care of it right? choose 1 and show it holds then sub in k for n and then k+1, then go from there? wooo!

then the seconnd one i just need to use that formula to get my odd numbers mod 11? muzza you are a LIFESAVER ! (no you are really)!
 

What is Modulo?

Modulo is a mathematical operation that finds the remainder after division of one number by another. It is represented by the symbol "%". For example, 10 % 3 = 1, because 10 divided by 3 is 3 with a remainder of 1.

What is Congruence?

Congruence is a term used to describe two numbers that have the same remainder when divided by a given number. For example, 7 and 10 are congruent when divided by 3, because they both have a remainder of 1.

How are Modulo and Congruence related?

Modulo and congruence are related because they both involve finding remainders after division. In fact, congruence can be thought of as a special case of modulo, where the remainder is being compared rather than calculated.

What are some real-world applications of Modulo and Congruence?

Modulo and congruence have many practical applications, such as in calculating leap years, determining patterns in repeating decimals, and creating secure encryption algorithms.

What are some common mistakes when working with Modulo and Congruence?

Some common mistakes when working with Modulo and Congruence include forgetting to include the remainder in the final answer, confusing congruence with equality, and not understanding the difference between a modulus and a divisor.

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