Question

I need help on this, please hurry and thank you!

Answer 1

`A.\ a_n=n^2+1`

Explanation:

`Check:`

`a_n=n^2+1\\\\a_1=1^2+1=1+1=2\qquad CORRECT\\\\a_2=2^2+1=4+1=5\qquad CORRECT\\\\a_3=3^2+1=9+1=10\qquad CORRECT\\\\a_4=4^2+1=16+1=17\qquad CORRECT\\\\a_5=5^2+1=25+1=26\qquad CORRECT`

Used PEMDAS:

P Parentheses first

E Exponents (ie Powers and Square Roots, etc.)

MD Multiplication and Division (left-to-right)

AS Addition and Subtraction (left-to-right)

First Power, next Addition

Answer 2

Answer: A.

Explanation:

2, 5, 10, 17, 26

First, check the difference between each term:

2 → 5 = +3

5 → 10 = +5

10 → 17 = +7

17 → 26 = +9

Since the difference (d) is not the same, this is not an arithmetic sequence.

Now, check the second tier {3, 5, 7, 9}

3 → 5 = 2

5 → 7 = 2

7 → 9 = 2

The difference (d) of the second tier is the same, so it is an exponential sequence.

--> the only option that is an exponential sequence is option A.