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Find sum to n terms of series 3.1² + 4.2² + 5.3²......

Bibek gautam , 6 Years ago
Grade 11
anser 1 Answers
Priyanka Bharti
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
Last Activity: 6 Years ago
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