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18 votes
18 votes
Find the indicated sum.
10
∑ (2j+8)
j=1

User Tprieboj
by
2.8k points

1 Answer

17 votes
17 votes

Answer: 190

Split the summation into smaller summations that fit the summation rules

10∑ j=1 (2j+8) = 2 10∑ j=1 (j) + 10 ∑ j=1 (8)

Firstly Evaluate

10

2 ∑ j=1 j

The formula for the summation of a polynomial with degree one is:

n∑ k=1 k =n (n+1) / 2

putting the values

2∑ j=1 j = (2)* 10 * (10+1) / 2

= 110…………………..(1)

second Evaluate :

10 ∑ j=1 (8)

The formula for the summation of a constant is:

N ∑ k=1 c = cn

Putting the values

10 ∑ j=1 (8) = 8 * 10

= 80……………….(2)

Adding both (1) and (2)

110+80

190

User SEJU
by
2.9k points