Question

Find the 8th term of the geometric sequence 4 , − 20 , 100

Answer 1

− 312500

Explanation:

Whenever looking at sequences, you have to attempt to find a common factor between the members of that sequence, be it the difference between them, a common divisor, a common multiplier, etc. In this case, we can see that if we divide each member by the previous one, we get a the same number:

100/-20 = -5

-20/4 = -5

So our sequence, starting at 4 is represented by the following recursive equation:

Hope this helps. :D