Question

Find the 20th term in the sequence, where the first term is -2 and the common ratio is-2.

Find a8 of the sequence 1,000, 200, 40, 8


What is the common ratio of a geometric sequence whose first term is 2 and whose 3rd term is 50.

Answer 1

Explanation:

(1)

a1=-2

r=-2

`a_(20)=(-2)(-2)^(20-1)=-2(-2)^(19)=2^(20)=1048576\\(2)\\a_(1)=1000\\r=(200)/(1000) =(1)/(5) \\a_(8)=1000((1)/(5) )^(8-1)=1000(.2)^7=0.0128\\(3)\\a_(1)=2\\a_(3)=50\\a_(2)=√(2*50) =10\\r=(10)/(2) =5`