Question

Can anyone please help me with these questions 2. a-b 3. a-b 4. a-b and number 5?

Answer 1

9514 1404 393

Answer:

2a. 0.7, 0.3, -0.1, -0.5, -0.9

2b. 1, 3, 9, 27, 81

3a. geometric; r = 1/5

3b. arithmetic; d = -9

4. 234

5. 1/32

Explanation:

2a. Start with the first term and add the common difference to get the next term.

0.7

0.7 -0.4 = 0.3

0.3 -0.4 = -0.1

-0.1 -0.4 = -0.5

-0.5 -0.4 = -0.9

The first 5 terms are 0.7, 0.3, -0.1, -0.5, -0.9.

__

2b. Start with the first term and multiply by the common ratio to get the next term.

The first 5 terms are 1, 3, 9, 27, 81.

__

3a. Obviously, the difference between 40 and 8 is not the same as the difference between 8 and 1.6. So, we look to see if the ratios are the same. They are:

8/40 = 1.6/8 = 1/5

This is a geometric sequence with a common ratio of 1/5.

__

3b. If the sign changes, but does not alternate, it cannot be a geometric sequence. The common difference is ...

-5 -4 = -14 -(-5) = -9

This is an arithmetic sequence with a common difference of -9.

__

4. Use n=50 and evaluate.

`a_(50)=-11+5(50-1)=\boxed{234}`

__

5. Use n=7 and evaluate.

`g_7=2\cdot\left((1)/(2)\right)^(7-1)=(2)/(2^6)=(1)/(2^5)=\boxed{(1)/(32)}`