# Geometric sequences

Having seen the sequences and series, right now there are 6 points I can make within the list stick to: 1. The nth term of the arithmetic series an = a1 + (n – 1) d 2. The sum of the arithmetic series Sn sama dengan n2a + (n – 1) d / 2 3. The sum of the initial n natural numbers in (n + 1) / 2 4. The nth term of the geometric sequence an = a1rn-1 5. Typically the sum of the finite geometric series S=a (rn-1) / (r-1) 6. If? ur?? 1, then the unlimited geometric series has sum a / (1 – r)