### Math Notes

Subjects

#### Algebra Solutions

##### Topics || Problems

Arithmetic progression (A.P.) is a sequence of numbers which is generated by adding a common difference (d) from the previous number.

Nth term of Arithmetic progression

Summation of Arithmetic progression

$$s =\frac{n}{2}(a_1 +a_2)$$

But: $$a_n = a_1 +d(n-1)$$

Thus:

$$S = \frac{n}{2} [a_1 +a_1 +d(n-1)]$$

$$S = \frac{n}{2} [2a_1 +d(n-1)]$$