Math Problem Statement

reduce 2^2016 mod 11

Solution

To reduce 22016mod112^{2016} \mod 11, we can again use Fermat's Little Theorem. This theorem states that for a prime number pp and any integer aa such that pp does not divide aa:

ap11modpa^{p-1} \equiv 1 \mod p

Here, p=11p = 11 and a=2a = 2. So, according to Fermat's Little Theorem:

2101mod112^{10} \equiv 1 \mod 11

To find 22016mod112^{2016} \mod 11, we first express 2016 in terms of multiples of 10:

2016=10×201+62016 = 10 \times 201 + 6

Thus,

22016=210×201+6=(210)201×262^{2016} = 2^{10 \times 201 + 6} = (2^{10})^{201} \times 2^6

Since 2101mod112^{10} \equiv 1 \mod 11, it follows that:

(210)20112011mod11(2^{10})^{201} \equiv 1^{201} \equiv 1 \mod 11

Therefore:

2201626mod112^{2016} \equiv 2^6 \mod 11

Now, calculate 262^6:

26=642^6 = 64

Finally, reduce 64mod1164 \mod 11:

64÷11=5 with a remainder of 964 \div 11 = 5 \text{ with a remainder of } 9

So:

649mod1164 \equiv 9 \mod 11

Thus,

220169mod112^{2016} \equiv 9 \mod 11

Would you like more details on the steps or any related concepts?

Here are five related questions you might find interesting:

  1. How can modular exponentiation be used in cryptography?
  2. What are some methods to efficiently compute large powers modulo a number?
  3. How does the Chinese Remainder Theorem relate to modular arithmetic?
  4. What is the significance of primitive roots in modular arithmetic?
  5. How can you determine the smallest positive integer xx such that ax1modpa^x \equiv 1 \mod p?

Tip: When working with large exponents in modular arithmetic, reducing the exponent first using the modulus can simplify calculations significantly.

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Math Problem Analysis

Mathematical Concepts

Modular Arithmetic
Exponentiation
Fermat's Little Theorem

Formulas

Fermat's Little Theorem: a^(p-1) ≡ 1 (mod p)

Theorems

Fermat's Little Theorem

Suitable Grade Level

Advanced High School