Last updated at Dec. 8, 2016 by
Transcript
Example 20, Find the sum to n terms of the series whose nth term is n (n+3). Given an = n (n + 3) = n2 + 3n The sum of n terms is = (n( n + 1)(2n + 1))/6 + (3n( n + 1) )/2 = (n(n + 1))/2 (( (2n + 1))/3 " + 3" ) = (n(n + 1))/2 (( (2n + 1) + 9)/3) = (n(n+1))/2 × (( 2𝑛 +10 )/3) = (n(n+1))/2 × ( 2(𝑛 +5) )/3 = (n( n + 1)(n + 5) )/3 Thus, the required sum is (n( n + 1)(n + 5) )/3
Finding sum from nth number
Ex 9.4, 8 Deleted for CBSE Board 2022 Exams
Ex 9.4, 10 Deleted for CBSE Board 2022 Exams
Ex 9.4, 9 Important Deleted for CBSE Board 2022 Exams
Ex 9.4, 1 Deleted for CBSE Board 2022 Exams
Ex 9.4, 5 Deleted for CBSE Board 2022 Exams
Ex 9.4, 7 Important Deleted for CBSE Board 2022 Exams
Misc 22 Important
Ex 9.4, 3 Deleted for CBSE Board 2022 Exams
Ex 9.4, 2 Important Deleted for CBSE Board 2022 Exams
Ex 9.4, 6 Important Deleted for CBSE Board 2022 Exams
Misc 25 Important Deleted for CBSE Board 2022 Exams
Misc 26 Deleted for CBSE Board 2022 Exams
Ex 9.4.4 Important Deleted for CBSE Board 2022 Exams
Misc 32 Important
Finding sum from nth number
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