PLEASE ANSWER THIS QUESTION......FROM MATHEMATICAL INDUCTION
Answers
Answer:
Step-by-step explanation:
Let P(n) be the statement that " 5ⁿ + 2×3ⁿ⁻¹ + 1 is divisible by 8 ".
There are two steps:
- Show that P(1) is true.
- Ahow that if P(k) is true, then P(k+1) is true.
Step 1
Putting n=1, the statement P(1) is " 5¹ + 2×3⁰ + 1 is divisible by 8 ".
5¹ + 2×3⁰ + 1 = 5 + 2×1 + 1 = 5 + 2 + 1 = 8, which is certainly divisible by 8.
So P(1) is true.
Step 2
Suppose for some k ≥1, the statement P(k) is true: " 5^k + 2×3^(k-1) + 1 is divisible by 8 ".
We must use this to establish that P(k+1) must then be true, too.
The statement P(k+1) is " 5^(k+1) + 2×3^k + 1 is divisible by 8 ".
5^(k+1) + 2×3^k + 1
= 5×5^k + 6×3^(k-1) + 1
= 5×5^k + 10×3^(k-1) + 5 - 4×3^(k-1) - 4
= 5×(5^k + 2×3^(k-1) + 1) - 4×( 3^(k-1) + 1 ) ... (*)
Since P(k) is true (the inductive hypothesis), the first term in (*) is divisible by 8. Since k ≥ 1, the value 3^(k-1) is odd => 3^(k-1) + 1 is even => the second term in (*) is divisible by 8.
Since both terms in (*) are divisible by 8, the whole expression is divisible by 8. It follows that 5^(k+1) + 2×3^k + 1 is divisible by 8, and so P(k+1) is true.
The claim now follows by mathematical induction.
let's us consider
s(n)=