21.Find the remainder when 2⁸¹ is divided by 17.
Answers
Answer:
Hi friends
Step-by-step explanation:
We are going to using congruence relation to find the remainder
We know that
2^5 = 32
⇒ 2^5 = 15(mod 17)
Taking square on both sides we get
⇒ (2^5)² = 15²(mod 17)
⇒ 2^10 = 225(mod 17)
And 225 = 4(mod 17) So
⇒ 2^10 = 4(mod 17)
Taking square on both sides we get
⇒ (2^10)² = 4²(mod 17)
⇒ 2^20 = 16(mod 17)
Taking square on both sides we get
⇒ (2^20)² = (16)²(mod 17)
⇒ 2^40 = 256(mod 17)
And 256 = 1(mod 17) So
⇒ 2^40 = 1 (mod 17)
Taking square on both sides we get
⇒ (2^40)² = 1² (mod 17)
⇒ 2^80 = 1 (mod 17)
Multiplying by 2 on both sides we get
(2^80) × 2 = 1 × 2 (mod 17)
⇒ 2^81 = 2 (mod 17)
Thus reminder is equal to 2 when 2^81 is divided by 17
❥︎ʀᴇᴍᴀɪɴᴅᴇʀ ɪs 2
strawberry ⁱˢ ᵗʸᵖⁱⁿᵍ