Euclidean Algorithm and Bezout's Theorem

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to Lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

Which set represents the natural numbers?

  • $ extbf{ℝ}$
  • $ extbf{ℕ}$ (correct)
  • $ extbf{ℤ}$
  • $ extbf{ℚ}$

If 2 divides 6, which statement is true?

  • 6 does not contain 2.
  • 6 is a factor of 2.
  • 2 is a multiple of 6.
  • 2 is a divisor of 6. (correct)

Why is the set of all integers ℤ not well ordered?

  • It contains negative integers.
  • It has no smallest element. (correct)
  • It is empty.
  • It is bounded above.

What property states that every nonempty set of natural numbers has a least element?

<p>Well-Ordering Principle (C)</p> Signup and view all the answers

Which of the following is a correct statement regarding divisibility?

<p>If $a|b$, there exists integer $c$ such that $b = ac$. (D)</p> Signup and view all the answers

Which of the following integers can divide zero?

<p>All integers including zero (D)</p> Signup and view all the answers

What is the smallest element of the set of positive integers?

<p>1 (D)</p> Signup and view all the answers

Which integers are the divisors of 17?

<p>$ ext{±1, ±17}$ (D)</p> Signup and view all the answers

What is the greatest common divisor (gcd) of 343 and 280?

<p>7 (A)</p> Signup and view all the answers

Which equation represents the process of finding integers x and y using the Euclidean Algorithm?

<p>7 = 343(9) - 280(11) (B)</p> Signup and view all the answers

What integers x and y satisfy the equation 343x + 280y = 7?

<p>9 and -11 (C)</p> Signup and view all the answers

According to Bezout's Theorem, if (a, b) = d, what can be concluded?

<p>There exist integers x and y such that a x + b y = d. (B)</p> Signup and view all the answers

In the process of finding x and y using quotients from the Euclidean Algorithm, what is the value of q3 in the given example?

<p>2 (C)</p> Signup and view all the answers

If d|ab and (d, a) = 1, which statement is correct according to the corollary?

<p>d must divide b. (C)</p> Signup and view all the answers

During which step of the Euclidean Algorithm does the remainder first become 7?

<p>From 28 to 7 (D)</p> Signup and view all the answers

What is the pattern used to derive the values of integers x and y from the quotients in the Euclidean Algorithm?

<p>Each subsequent value is a product of the previous value multiplied by a quotient. (D)</p> Signup and view all the answers

What can be concluded if 11 divides both 66 and 198?

<p>11 divides 66 and 66 divides 198. (C)</p> Signup and view all the answers

If d is a divisor of both a and b, what can be definitely stated about c in terms of a + b?

<p>c is a divisor of a + b. (D)</p> Signup and view all the answers

How is the greatest common divisor (gcd) defined?

<p>It is the largest number that divides both a and b without leaving a remainder. (A)</p> Signup and view all the answers

Which statement is true regarding the existence of the gcd of two integers?

<p>The gcd is not defined if either integer is zero. (A)</p> Signup and view all the answers

In the example of having 100 coins made up of pennies, dimes, and quarters totaling exactly $5.00, what conclusion can be drawn?

<p>It is impossible to have 100 coins worth exactly $5.00. (C)</p> Signup and view all the answers

If d divides 4 and 14, what can be the possible values of d?

<p>2 (D)</p> Signup and view all the answers

What can be said about the gcd of two integers where one of them is prime?

<p>It is either 1 or the prime number itself. (B)</p> Signup and view all the answers

What is the result of the expression 5(21) - 3(33) in terms of divisibility?

<p>The result is divisible by 3. (C)</p> Signup and view all the answers

What is the result of (n, 1) where n is any positive integer?

<p>1 (B)</p> Signup and view all the answers

What is the greatest common divisor of a positive integer a and 2a?

<p>a (B)</p> Signup and view all the answers

If (a, b) = d, what is the relationship between (a/d, b/d) and 1?

<p>(a/d, b/d) = 1 (C)</p> Signup and view all the answers

What can be said about the integers q and r in the Division Algorithm?

<p>They are unique integers. (A)</p> Signup and view all the answers

What is the value of (n, 0) for any integer n?

<p>n (B)</p> Signup and view all the answers

Which pair of integers is an example of relatively prime numbers?

<p>(25, 42) (C)</p> Signup and view all the answers

What guarantees that the integers q and r from the Division Algorithm are unique?

<p>The remainder must be less than b. (A)</p> Signup and view all the answers

If d and n are any integers, what is the greatest common divisor of (d, nd)?

<p>d (D)</p> Signup and view all the answers

In the expression $a = bq + r$, what does 'r' represent?

<p>Remainder (D)</p> Signup and view all the answers

Given $a = -50$ and $b = 8$, what are the values of q and r respectively?

<p>-7 and 6 (C)</p> Signup and view all the answers

What guarantees the end of the sequence of remainders in the Euclidean Algorithm?

<p>A remainder eventually becomes zero. (C)</p> Signup and view all the answers

If $gcd(a, b) = d$, which of the following statements is true according to Bezout's Theorem?

<p>There exist integers x and y such that $ax + by = d$. (B)</p> Signup and view all the answers

What can be concluded if both $a$ and $b$ are negative in the context of gcd?

<p>The gcd remains unchanged as $(|a|, |b|)$. (C)</p> Signup and view all the answers

What are the values of q and r for the case $a = 75$ and $b = 24$?

<p>4 and 3 (C)</p> Signup and view all the answers

What condition must be upheld for the remainder r in the division $a = bq + r$?

<p>$0 eq r$ and $r &lt; b$. (D)</p> Signup and view all the answers

What is the first step in applying the Euclidean Algorithm to calculate gcd?

<p>Set up the equation $a = bq + r$. (B)</p> Signup and view all the answers

Flashcards are hidden until you start studying

Study Notes

Euclidean Algorithm

  • The Euclidean Algorithm is a method for determining the greatest common divisor (GCD) of two integers, denoted as (𝑎, 𝑏) or 𝑔𝑐𝑑(𝑎, 𝑏).
  • The algorithm works by repeatedly finding the remainders of divisions until a remainder of 0 is reached.
  • The final non-zero remainder is the GCD of the original two integers.
  • Example:
    • 343 = 280(1) + 63
    • 280 = 63(4) + 28
    • 63 = 28(2) + 7
    • 28 = 7(4) + 0
  • Therefore, gcd(343, 280) = 7.

Bezout's Theorem

  • Bezout's Theorem states that for two integers a and b, there exist integers x and y such that ax + by = d, where d is the greatest common divisor of a and b.
  • This theorem can be proven by working the Euclidean algorithm backwards, expressing the GCD (d) as a linear combination of the original integers.
  • To find x and y, we can use two methods:
    • Method 1: Use the remainders in the Euclidean Algorithm:
      • Express each remainder as the difference of two integers in the corresponding equation.
      • Substitute the remainder in the previous equation with this expression and continue this process until you reach the equation where the GCD (d) is expressed as a linear combination of the original integers.
    • Method 2: Use the quotients in the Euclidean Algorithm:
      • Create a table with the quotients from the divisions in the Euclidean Algorithm, starting with q1 and going down to qn, where qn is the final quotient.
      • Calculate the s-values and t-values for each step, starting from the bottom of the table.
      • For the s-values, use the formula: sn = qn-1 * sn-1 + sn-2, where qn-1 is the quotient used in the step.
      • For the t-values, use the formula: tn = qn-1 * tn-1 + tn-2.
      • The final s-value, 𝑠n, will be x, and the final t-value, 𝑡n, will be y.

Examples

  • Example (Method 1):
    • Find x and y such that 343x + 280y = gcd(343, 280).
    • Using the remainders in the Euclidean Algorithm:
      • 7 = 63 - 28(2)
      • 7 = 63 - (2)(280 - 63(4)) = 63(9) - 280(2)
      • 7 = 9(343 - 280) - (2)280 = 343(9) - 280(11)
    • Therefore, 7 = 343(9) + 280(-11), and we can take x = 9 and y = -11.
  • Example (Method 2):
    • Find x and y such that 343x + 280y = gcd(343, 280).
    • Using the quotients from the Euclidean Algorithm:
      • q1 = 1, q2 = 4, q3 = 2, q4 = 4
    • Create a table with s-values and t-values:
      q1 q2 q3 q4
      0 1 4 9
      0 1 5 11
    • Therefore, x = 9 and y = -11.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Quiz Team

Related Documents

More Like This

Euclidean Algorithm and GCD Quiz
5 questions
Algebra Class: Inverses and GCD
44 questions

Algebra Class: Inverses and GCD

ArticulateArcticTundra9680 avatar
ArticulateArcticTundra9680
最大公约数 (GCD) 的计算方法
8 questions
Use Quizgecko on...
Browser
Browser