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प्रश्न
Find the sum to n terms of the series 3 × 12 + 5 × 22 + 7 × 32 + …
उत्तर
The given series is 3 ×12 + 5 × 22 + 7 × 32 + …
nth term, an = ( 2n + 1) n2 = 2n3 + n2
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