What is the formula for calculating the sum of consecutive integers?

[mtayab1994]

Homework Statement

$$1+2+3...+n$$

Homework Equations

count the sum.

The Attempt at a Solution

it's such an easy sum to count but i just want to make sure.

$$S_{n}=\frac{n}{2}(a_{1}+a_{n})$$


$$S_{n}=\frac{n}{2}(1+n)$$


$$S_{n}=\frac{n+n^{2}}{2}$$

 

[Gengar]

Correct. Hope your anxiety is eased

 

[mtayab1994]

Lol its too simple idk why my teacher would give us something so simple I thought there would be a trick or something.