#### The sum of an arithmetic series is \sum_{r = 1}^{n} (80 - 3r)

Given that n = 50,

Find the sum of the series.

Anonymous

0

Given that n = 50,

Find the sum of the series.

Krishna

0

Step 1: To find the 1st term, plug in n = 1. in the sequence and simplify

[NOTE: Knowing that, n represents the position of a term in the sequence. So change the n values.]

Step 2: To find the 2nd term, plug in n = 2. In the sequence and simplify

Step 3: Take the various n values and substitute in the sequence, till you get the required sequence.

Step 5: Find the sum of the series.

Skill i: Identify the first term in the sequence, call this number a.

Skill ii: Calculate the common difference(d) of the sequence.

Skill iii: Identify the number of terms (n).

EXAMPLE: In A.P 2, 4, 6,..... find the sum of the first 10 terms. So take n=10

Skill iv: Plug the values of n, d, and a into the formula.

[FORMULA: The formula for finding the sum of first n terms of an

arithmetic sequence (S_n) =(n/2)[2a + (n- 1)d]

Skill v: Simplify further..(Apply the BODMAS rules)