Question

find the first 4 terms of the geometric sequence a1=40 and r=0.5

Answer 1

For the answer to the question above, 
a1 = 40 
a2 = 20 
a3 = 10 
.. 
aN = (1/2^N-1) a1 { in general aN= (r^N-1) A1 

a5 = (1/2^4) 40 = 40/16 = 2.5

So the answer to your question is 2.5
I hope my answer helped you. Feel free to ask more questions. Have a nice day!

Answer 2

Answer:

So the answer to your question is 2.5. Thanks to MissPhiladelphia for her answer.

Step-by-step explanation:

For the answer to the question above,  

a1 = 40  

a2 = 20  

a3 = 10  

..  

aN = (1/2^N-1) a1 { in general aN= (r^N-1) A1  

a5 = (1/2^4) 40 = 40/16 = 2.5