Problem 57

Question

Find the sum of the finite arithmetic sequence. $$2+4+6+8+10+12+14+16+18+20$$

Step-by-Step Solution

Verified
Answer
The sum of the arithmetic sequence is 110.
1Step 1: Identify the first term, last term, and number of terms
Observe the sequence: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20. It can be seen that the first term \(a_l\) is 2, the last term \(a_n\) is 20, and the number of terms \(n\) is 10.
2Step 2: Apply the formula for the sum of an arithmetic sequence
The formula for the sum of an arithmetic sequence is: \(S = \frac{n}{2} (a_l + a_n)\). Substituting the identified values from Step 1 into the formula gives: \(S = \frac{10}{2} (2 + 20)\)
3Step 3: Calculate the sum
Calculate the sum \(S\) as per the substituted formula: \(S = 5 * 22 = 110\)