Question

Find the 12th term of geometric sequence 10,-50,250,...

Answer 1

Step-by-step explanation:

Use the explicit formula for a geometric sequence:

a

n

=

a

1

(

r

)

n

−

1

Explanation:

First, find the common ratio

r

=

10

2

=

5

Now, insert the values from the problem into the explicit formula ...

a

n

=

2

(

5

)

n

−

1

So, for example if you want to know the 11th term ...

a

11

=

2

(

5

)

(

11

−

1

)

=

19

,

531

,

250

[wow! that's a big number!]

Hope that helped!