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| General Series |
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| 1. To find the sum of first n natural numbers. |
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| Suggested answer: |
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| Let Sn = 1+2+3+4+...+n |
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| This series is an A.P. |
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| Here a=1, d=1, l = tn = n |
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| 2. To find the sum to squares of first n natural numbers. |
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| Adding vertically, |
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| 3. To find the sum to the cubes of first n natural numbers. |
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| Adding vertically, |
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| 4. Method of finding sum of a series whose nth term is known. |
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| Suggested answer: |
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| Let the nth term of series be an3 + bn2 + cn + d |
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| tn = an3 + bn2 + cn + d where a, b, c, d are constants. |
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