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PLEASE PLEASE HELP!! Write a recursive and explicit formula for the following sequences.

1) -4, -8, -16, -32...

Recursive:
Explicit:

2) 320, 80, 20, 5...

Recursive:
Explicit:
Find the 7th term

3) 10, 40, 70, 100...

Recursive:
Explicit:

4) 4, 7, 10, 13...

Recursive:
Explicit:

Find the 11th term.

1 Answer

1 vote

1) -4, -8, -16, -32...

Recursive Formula: f(1)=-4, f(n) = 2*f(n-1)

Explicit Formula: f(n) = -2ⁿ where n>1

11th term = f(11) = -2¹²=-4096

2) 320, 80, 20, 5...

Recursive Formula: f(1)=320, f(n) =f(n-1)/4

Explicit Formula: f(n)=320/4ⁿ⁻¹

11th term = f(11) = 320/4¹⁰ =

3) 10, 40, 70, 100...

Recursive Formula: f(1)=10, f(n)=f(n-1)+30

Explicit Formula: f(n)=10+30(n-1)

11th term = f(11) = 10+30(10) = 310

4) 4, 7, 10, 13...

Recursive Formula: f(1)=4 and f(n)=f(n-1)+3

Explicit Formula: f(n)=4+3(n-1)

11th term = f(11) = 4+3(10)=34

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