106k views
5 votes
What is the 20th term of the sequence that begins -4, 8, -16, 32...?

1 Answer

5 votes

Answer:

-2097152 is the 20th term

Explanation:

Write geometric sequence as an explicit formula


-4,8,-16,32\rightarrow-4(-2)^0,-4(-2)^1,-4(-2)^2,4(-2)^3\\a_n=a_1r^(n-1)\rightarrow a_n=-4(-2)^(n-1)

Find the n=20th term


a_(20)=-4(-2)^(20-1)=-4(-2)^(19)=4(-524288)=-2097152

User Sbernard
by
7.8k points

No related questions found

Welcome to QAmmunity.org, where you can ask questions and receive answers from other members of our community.

9.4m questions

12.2m answers

Categories