Q. Find the sum of the first 35 terms of the following series, to the nearest integer.11,17,23,…Answer:
Identify Terms: Identify the first term a1 and the common difference d of the arithmetic series.The first term a1 is 11.To find the common difference, subtract the first term from the second term: d=17−11=6.
Calculate Common Difference: Use the formula for the sum of the first n terms of an arithmetic series: Sn=2n×(2a1+(n−1)d). Here, n=35, a1=11, and d=6.
Use Sum Formula: Substitute the values into the formula to calculate the sum: S35=235×(2×11+(35−1)×6).
Substitute Values: Perform the calculations inside the parentheses first: 2×11=22 and (35−1)×6=34×6=204.
Perform Calculations: Now, add the results inside the parentheses: 22+204=226.
Multiply Result: Multiply the result by n/2: S35=235×226.
Calculate Final Sum: Calculate the sum: S35=17.5×226=3955.
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