Find sum to n terms of series 3.1² + 4.2² + 5.3²......
Bibek gautam , 5 Years ago
Grade 11
Magical Mathematics[Interesting Approach]> Find sum to n terms of series 3.1² + 4.2²...
1 AnswersPriyanka Bharti
Last Activity: 5 Years ago
3×1^2 + 4×2^2 + 5×3^2 +.......
= (1+2)×1^2 + (2+2)×2^2 + (3+2)×3^2 + ..
= 1^3 +2×1^2 + 2^3 + 2×2^2 + 3^3 + 2×3^2 +... .
= ( 1^3 + 2^3 + 3^3 + . . . . .) +2(1^2 + 2^2 + 3^2 +... . )
Then apply formula and get the solution
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