Question

Sequence: 13, 11, 9, 7, .. an = an-1 a1 =​

Answer 1

Answer:

a

n

=

−

2

n

+

15

Step-by-step explanation:

This is an arithmetic sequence since there is a common difference between each term. In this case, adding

−

2

to the previous term in the sequence gives the next term. In other words,

a

n

=

a

1

+

d

(

n

−

1

)

.

Arithmetic Sequence:

d

=

−

2

This is the formula of an arithmetic sequence.

a

n

=

a

1

+

d

(

n

−

1

)

Substitute in the values of

a

1

=

13

and

d

=

−

2

.

a

n

=

13

+

(

−

2

)

(

n

−

1

)

Simplify each term.

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a

n

=

13

−

2

n

+

2

Add

13

and

2

.

a

n

=

−

2

n

+

15