Math Problem Statement

Compute the following expression in 𝔽67.

[15] βˆ’ [22]

[8] β‹… [14]

Solution

To compute the expression in the finite field F67\mathbb{F}_{67}, we will follow these steps:

Expression:

[ \frac{[15] - [22]}{[8] \cdot [14]} ]

Step 1: Compute [15]βˆ’[22][15] - [22] in F67\mathbb{F}_{67}

15βˆ’22=βˆ’715 - 22 = -7 In F67\mathbb{F}_{67}, we need to reduce this modulo 67: βˆ’7≑60mod  67-7 \equiv 60 \mod 67 So, [15]βˆ’[22]≑60mod  67[15] - [22] \equiv 60 \mod 67.

Step 2: Compute [8]β‹…[14][8] \cdot [14] in F67\mathbb{F}_{67}

8Γ—14=1128 \times 14 = 112 Now, reduce this modulo 67: 112mod  67=45112 \mod 67 = 45 So, [8]β‹…[14]≑45mod  67[8] \cdot [14] \equiv 45 \mod 67.

Step 3: Compute the final result in F67\mathbb{F}_{67}

Now, we need to find the expression 6045\frac{60}{45} modulo 67. This can be expressed as: 6045≑60Γ—45βˆ’1mod  67\frac{60}{45} \equiv 60 \times 45^{-1} \mod 67 where 45βˆ’145^{-1} is the multiplicative inverse of 45 modulo 67.

Step 4: Find the inverse of 45 modulo 67

Using the Extended Euclidean Algorithm or trial and error, we find that the inverse of 45 modulo 67 is 37.

Step 5: Multiply and reduce the result modulo 67

60Γ—37=222060 \times 37 = 2220 Now reduce this modulo 67: 2220mod  67=62220 \mod 67 = 6

Final Answer:

[ \frac{[15] - [22]}{[8] \cdot [14]} \equiv 6 \mod 67 ]

The final answer is 66 in F67\mathbb{F}_{67}.

Would you like more details or have any questions?


Related Questions:

  1. How do you find the multiplicative inverse in a finite field?
  2. Why is modular arithmetic important in number theory?
  3. How can you verify your computations in finite fields?
  4. What are common applications of finite fields in cryptography?
  5. How does the Extended Euclidean Algorithm work?
  6. Can you compute similar expressions in other finite fields?
  7. What happens if there is no inverse for the divisor in a finite field?
  8. How are finite fields used in error detection and correction?

Tip: Understanding how to find inverses in a finite field is crucial for solving division problems in modular arithmetic.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Finite Fields
Modular Arithmetic
Multiplicative Inverse

Formulas

Modular Arithmetic
Extended Euclidean Algorithm

Theorems

Existence of Multiplicative Inverse in Finite Fields

Suitable Grade Level

Advanced High School