Q. Find the sum of the first 38 terms of the following series, to the nearest integer.2,11,20,…Answer:
Identify type and difference: Identify the type of series and the common difference.The series given is arithmetic because there is a constant difference between consecutive terms.To find the common difference, subtract the first term from the second term.11−2=9Common Difference: 9
Find 38th term: Find the 38th term of the series using the formula for the nth term of an arithmetic series.The nth term an of an arithmetic series can be found using the formula:an=a1+(n−1)dwhere a1 is the first term, d is the common difference, and n is the term number.For the 38th term:a38=2+(38−1)×9a38=2+37×9a38=2+333a38=335
Calculate sum of terms: Calculate the sum of the first 38 terms using the formula for the sum of an arithmetic series.The sum Sn of the first n terms of an arithmetic series can be found using the formula:Sn=2n×(a1+an)where a1 is the first term and an is the nth term.For the sum of the first 38 terms:S38=238×(2+335)S38=19×337S38=6403