Question

formulas in the chapters Aritlimetic Progressi​

Answer 1

Answer:

there are mainly two formula

1)

$a |n = a + ( - 1)d$

it's for finding the n th term of an AP

2)

$s |n = \frac{n}{2} \: (2a + (n - 1)d)$

it's for calculation the sum value of AP

Answer 2

Answer:

an = a+(n- 1)d

sn= 2a+(n-1)

sn= n/ 2 ( 2a +(n-1) d . etc.....