Are Multiplicative Inverses in Z_n Equivalent Modulo n?

In summary, a multiplicative inverse, also known as a reciprocal, is a number that when multiplied by a given number, results in a product of 1. It can be proved using the property of fractions and is always unique. However, not every number has a multiplicative inverse as it must not be equal to 0. The multiplicative inverse is often used in solving equations by "undoing" the effect of multiplication.
  • #1
kathrynag
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Homework Statement


Show that if and [c] are multiplicative inverses of [a] in [tex]Z_{n}[/tex], then b[tex]\equiv[/tex]c mod n.


Homework Equations





The Attempt at a Solution


I'm totally confused on this.
 
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  • #2
[a]=1 and [a][c]=1, right?
 

FAQ: Are Multiplicative Inverses in Z_n Equivalent Modulo n?

1. What is a multiplicative inverse?

A multiplicative inverse, also known as a reciprocal, is a number that when multiplied by a given number, results in a product of 1. In other words, it is the number that "undoes" the effect of multiplication.

2. How do you prove the multiplicative inverse of a number?

The multiplicative inverse of a number can be proved using the property of fractions that states: a/b = 1 if and only if b/a = 1. Therefore, to prove the multiplicative inverse of a number, we need to show that when multiplied together, the number and its inverse result in a product of 1.

3. Is the multiplicative inverse of a number always unique?

Yes, the multiplicative inverse of a number is always unique. This is because if there were two different numbers that when multiplied together resulted in a product of 1, they would essentially be the same number, just written in different forms.

4. Can every number have a multiplicative inverse?

No, not every number has a multiplicative inverse. In order for a number to have a multiplicative inverse, it must not be equal to 0. This is because when a number is multiplied by 0, the result is always 0, not 1.

5. How is the multiplicative inverse used in solving equations?

The multiplicative inverse is used in solving equations by "undoing" the effect of multiplication. For example, if a variable is being multiplied by a number, we can divide both sides of the equation by the same number (its multiplicative inverse) to isolate the variable and solve for its value.

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