Question

What is the explicit formula for this geometric sequence? 5,10,20,40,80,160,...

Answer 1

Answer:

  an = 5·2^(n-1)

Step-by-step explanation:

The explicit formula for a geometric sequence with first term a1 and common ratio r is ...

  an = a1·r^(n-1)

Your sequence has a1=5 and r=2, so the explicit formula is ...

  an = 5·2^(n-1)