Question

Find the sum of the first 25 terms of the Arithmetic sequence 12, 23,34

Answer 1

The sum of the members of a finite arithmetic progression is called an arithmetic series.

Using our example, consider the sum:

12+23+34+45+56+67+78+89

This sum can be found quickly by taking the number n of terms being added (here 8), multiplying by the sum of the first and last number in the progression (here 12 + 89 = 101), and dividing by 2:

n(a1+an)

2

8(12+89)

2

The sum of the 8 members of this series is 404

This series corresponds to the following straight line y=11x+12

Answer 2

Answer:

12+23+34+45+56+67+78+89

This sum can be found quickly by taking the number n of terms being added (here 8), multiplying by the sum of the first and last number in the progression (here 12 + 89 = 101), and dividing by 2:

n(a1+an)

2

8(12+89)

2

The sum of the 8 members of this series is 404

Step-by-step explanation: