Answer:
n = 5 terms
Step-by-step explanation:
An = a1 + (n-1)d
9 = 3 + (n-1) 3/2
9 = 3 + 3/2n - 3/2
9 = 3/2 + 3/2n
9 - 3/2 = 3/2n
(15/2) / (3/2) = n
30/6 = n
11th term is 10240
Step-by-step explanation:
- Step 1: Given the sequence 10,20,40. So a(1) = 10, common ration, r = 20/10 = 2 Find the 11th term using the nth term formula, a(n) = ar^n-1
⇒ a(11) = 10 × 2^10 = 10 × 1024 = 10240
I am attaching a document showing the steps.