Respuesta :

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

Step-by-step 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.

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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.

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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.

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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.

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4. Use n=50 and evaluate.

  [tex]a_{50}=-11+5(50-1)=\boxed{234}[/tex]

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5. Use n=7 and evaluate.

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