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Show that 10 is a primitive root of 17 (15 pts). Then use your work to calculate the discrete logarithm of 12 base 10 (with prime modulus 17) (5 pts).

a. True
b. False

1 Answer

3 votes

Final answer:

The statement that ` 10 is a primitive root of 17` is FALSE because the discrete logarithm of 12 base 10 with modulus 17 is 15.

The answer is option ⇒b. False.

Step-by-step explanation:

To show that 10 is a primitive root of 17, we need to check whether the powers of 10, when taken modulo 17, produce all the non-zero residues (1, 2, 3, ..., 16).

Let's calculate the powers of 10 modulo 17:

10¹ ≡ 10 (mod 17)

10² ≡ 100 ≡ 16 (mod 17)

10³ ≡ 1000 ≡ 13 (mod 17)

10⁴ ≡ 10000 ≡ 4 (mod 17)

10⁵ ≡ 100000 ≡ 7 (mod 17)

10⁶≡ 1000000 ≡ 11 (mod 17)

10⁷ ≡ 10000000 ≡ 9 (mod 17)

10⁸ ≡ 100000000 ≡ 6 (mod 17)

10⁹ ≡ 1000000000 ≡ 14 (mod 17)

10¹⁰ ≡ 10000000000 ≡ 3 (mod 17)

10¹¹ ≡ 100000000000 ≡ 8 (mod 17)

10¹² ≡ 1000000000000 ≡ 5 (mod 17)

10¹³ ≡ 10000000000000 ≡ 15 (mod 17)

10¹⁴ ≡ 100000000000000 ≡ 2 (mod 17)

10¹⁵ ≡ 1000000000000000 ≡ 12 (mod 17)

10¹⁶ ≡ 10000000000000000 ≡ 1 (mod 17)

As we can see, the powers of 10 modulo 17 produce all the non-zero residues (1, 2, 3, ..., 16). This means that 10 is a primitive root of 17.

To calculate the discrete logarithm of 12 base 10 (with prime modulus 17), we need to find the exponent k such that 10ᵏ ≡ 12 (mod 17).

By checking the powers of 10 modulo 17 above, we can see that 10¹⁵ ≡ 12 (mod 17). Therefore, the discrete logarithm of 12 base 10 with modulus 17 is 15.

Based on the above calculations, the answer is:

b. False

User Maha Lak
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