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Show that `a_(1), a_(2), ….,a_(n),…` form an A.P where an is defined as below : (i) `a_(n) = 3 + 4n` (ii) `a_(n) = 9 - 5n`.
Also find the sum of the first 15 terms in each case.

Text Solution

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The correct Answer is:
(i) 525, (ii) `- 465`
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