arithmetic

Question 1

sum of n terms for arithmetic

Answer 1

Sn = (n/2) [2a1 + (n - 1) d] (or) (n/2) [a1 + an]

Question 2

arithmetic formula

Answer 2

an = a1 + (n - 1) d

Question 3

geometric sequence formula

Answer 3

an = a1(r)^n-1

Question 4

sum of n terms for geometric sequence

Answer 4

sn = a1(1-rn) / 1-r