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 need to perform the operations modulo 67. The expression is:

[ \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 Since we're working in F67\mathbb{F}_{67}, we need to find the equivalent value 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, find 112mod  67112 \mod 67: 112mod  67=45112 \mod 67 = 45 So, [8]β‹…[14]≑45mod  67[8] \cdot [14] \equiv 45 \mod 67.

Step 3: Compute the multiplicative inverse of 45 in F67\mathbb{F}_{67}

To find 6045\frac{60}{45} in F67\mathbb{F}_{67}, we need the multiplicative inverse of 45 modulo 67. This means finding xx such that: 45x≑1mod  6745x \equiv 1 \mod 67 Using the Extended Euclidean Algorithm, we find that the inverse of 45 modulo 67 is 37.

Step 4: Multiply the result of Step 1 by the inverse found in Step 3

6045≑60Γ—37mod  67\frac{60}{45} \equiv 60 \times 37 \mod 67 60Γ—37=222060 \times 37 = 2220 Now, find 2220mod  672220 \mod 67: 2220mod  67=62220 \mod 67 = 6

Final Answer:

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

Would you like more details or have any questions?


Related Questions:

  1. How do you find the multiplicative inverse of a number in Fp\mathbb{F}_p?
  2. What is the general method for solving division in finite fields?
  3. How does the Extended Euclidean Algorithm work in finding inverses?
  4. Can you explain the properties of arithmetic in Fp\mathbb{F}_p?
  5. What would happen if the divisor had no inverse in F67\mathbb{F}_{67}?
  6. How do you perform addition and subtraction in finite fields?
  7. What is modular arithmetic, and why is it important in finite fields?
  8. Can you give an example of a real-world application where finite fields are used?

Tip: When working in a finite field, always ensure the divisor has an inverse before dividing.

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Math Problem Analysis

Mathematical Concepts

Finite Fields
Modular Arithmetic
Multiplicative Inverse

Formulas

Modular arithmetic operations
Extended Euclidean Algorithm

Theorems

Existence of multiplicative inverses in finite fields

Suitable Grade Level

Advanced Mathematics