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PLS HELP
1.
Seats in a theater are curved from the front row to the back. The front row has 18 chairs, the second has 26
and the third has 34, and so on.
a.
Write a recursive rule for this series (2 points):
b. Write an explicit rule in simplified form for this series:
Show the steps to simplify. (2 points)
c. Using the explicit formula, find the number of chairs in row 7 (show work) (3 points):
on Voy bob ochote
bu ma'isto
d. The auditorium can hold 12 rows of chairs. Write a sigma notation for this series, and then use either series
formulas to calculate how many chairs can fit in the auditorium. Show all work. (5 points)

Respuesta :

MrRoyal

The chairs in the auditorium illustrates an arithmetic sequence

  • The recursive rule is:  an = an-1 + 8; a1 = 26
  • The explicit rule is:  an = 18 + 8n
  • There are 74 seats in the 7th row
  • 840 chairs can fit the auditorium

The recursive rule

From the question, we have the following sequence:

Seats: 18, 26, 34

Rewrite as:

26 = 18 + 8

34 = 26 + 8

The above means that:

The number of seats on a row is 8 added to the the number of seats on the previous row.

Hence, the recursive rule is:

an = an-1 + 8; a1 = 26

The explicit rule

In (a), we have:

a1 = 26 and d = 8

The explicit rule is calculated using:

an = a1 + (n -1) * d

This gives

an = 26 + (n - 1) * 8

Expand

an = 26 - 8 + 8n

Evaluate the difference

an = 18 + 8n

Hence, the explicit rule is:

an = 18 + 8n

The number of seats in the row 7

This means that n = 7.

So, we  have:

a7 = 18 + 8 * 7 = 74

Hence, there are 74 seats in the 7th row

The sigma notation

We have the maximum number of rows to be 12.

So, the sigma notation would be:

[tex]\sum\limits^{12}_{n=1} {18 + 8n}[/tex]

The total number of seats is:

Sn = n/2(2a + (n -1) * d)

This gives

S12 = 12/2(2 * 26 + (12 -1) * 8)

S12 = 840

Hence, 840 chairs can fit the auditorium

Read more about arithmetic sequence at:

https://brainly.com/question/6561461

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