Math Problem Statement

Compute 50^256 (mod 37).

Solution

Let's analyze the problem in detail.

We are asked to compute 50256mod3750^{256} \mod 37 and check which of the provided statements are correct.

Approach:

  1. Simplify the base modulo 37: First, reduce 50mod3750 \mod 37: 505037=13(mod37)50 \equiv 50 - 37 = 13 \pmod{37} So, 50256mod37=13256mod3750^{256} \mod 37 = 13^{256} \mod 37.

  2. Use Euler's Theorem: Euler’s theorem states that if aa and nn are coprime (i.e., gcd(a,n)=1\gcd(a, n) = 1), then aϕ(n)1(modn)a^{\phi(n)} \equiv 1 \pmod{n}, where ϕ(n)\phi(n) is Euler’s totient function. Since gcd(13,37)=1\gcd(13, 37) = 1 and 3737 is a prime number, ϕ(37)=371=36\phi(37) = 37 - 1 = 36. Therefore: 13361(mod37)13^{36} \equiv 1 \pmod{37}

  3. Reduce the exponent modulo 36: To simplify 13256mod3713^{256} \mod 37, reduce the exponent 256mod36256 \mod 36: 256÷36=7 remainder 4256 \div 36 = 7 \text{ remainder } 4 So, 2564(mod36)256 \equiv 4 \pmod{36}, which implies: 13256134(mod37)13^{256} \equiv 13^4 \pmod{37}

  4. Calculate 134mod3713^4 \mod 37: Now calculate 134mod3713^4 \mod 37: 132=16922(mod37)13^2 = 169 \equiv 22 \pmod{37} 134=(132)2=222=48434(mod37)13^4 = (13^2)^2 = 22^2 = 484 \equiv 34 \pmod{37}

Thus, 5025634(mod37)50^{256} \equiv 34 \pmod{37}.

Conclusion:

The correct answer is 5025634(mod37)50^{256} \equiv 34 \pmod{37}, which matches the third statement. Therefore, the third option is the correct one.

Let me know if you'd like any further clarification or details.

Here are five related questions:

  1. How do we use Euler's theorem to simplify large exponentiation in modular arithmetic?
  2. What is Euler's totient function and how is it computed for prime numbers?
  3. How do you compute abmodna^b \mod n efficiently using exponentiation by squaring?
  4. What are the conditions for applying Euler's theorem in modular arithmetic problems?
  5. Can the Chinese Remainder Theorem be used in similar modular exponentiation problems?

Tip: Always try to reduce the base and exponent in modular arithmetic to keep calculations manageable.

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Math Problem Analysis

Mathematical Concepts

Modular Arithmetic
Exponentiation
Number Theory

Formulas

a^b (mod n)
a^φ(n) ≡ 1 (mod n) when gcd(a, n) = 1
Euler's Totient function: φ(n) = n - 1 for prime n

Theorems

Euler's Theorem
Exponentiation Modulo

Suitable Grade Level

Grades 11-12, College